Best Setup for Mapping in Undeveloped Countries?

Floodimus asks: "My girlfriend lives and works in West Africa and on my next visit she has asked me to help her do some mapping of uncharted villages. I want to make this study really accurate and useful, so I am thinking about using high tech and low tech resources such as GPS and good old fashioned compasses, but I was wondering what the Slashdot crowd would recommend for GPS hardware (does GPS equipment from the US work over there?), field equipment, mapping software etc. I use both PCs and Macs and would like the software to run on the Mac, but it doesn't have to. What's the best, most rugged stuff you've used? Where are some resources that would help me out?"

Comments

Hello?

[AKAImBatman]

does GPS equipment from the US work over there?

Ok, a quick explanation of how this stuff works is in order. GPS stands for Global Positioning System. The system consists of 24 or so satellites that provide nearly complete coverage of the globe at any given time. By capturing signals from more than one of these satellites, your receiver can calculate your position based on the last known position of the sats. Thanks to the precision and accuracy of modern electronic hardware, this calculation can be accurate to within 20 meters or less.

More info here

So to answer your question, of course GPS equipment can't be used over there! They use 220V AC and we use 110V AC. Where do you think you're going to find a charger? You need to get yourself a step down transformer, or you'll never be able to charge the equipment! Yeash, what are they teaching you kids these days?

Re:Hello?

[dieman]

Well, we use 120VAC, rather. 100VAC-230VAC AC-DC adaptors are common with equipment these days, however. You may want to look for equipment that comes with such an adaptor instead of trying to step it down. Heck, even my cell phone came with one that can do 100-230.

Re:Hello?

[hyfe]

There's plenty of GPS-equipment that run on batteries though. If he's going to be trecking through Africa, that is most likely his best bet anyways.

Re:Hello?

[AKAImBatman]

It's supposed to be funny. Laugh. :-)

Re:Hello?

[tigerc]

Many of the adapters that come with laptops today accept 120/240, 50-60 hz. All you need then is a power adapter for the outlet.

Re:Hello?

[molecular]

By capturing signals from more than one of these satellites, your receiver can calculate your position based on the last known position of the sats.

read the wikipedia-article you referenced. Surely, 2 satellites are not enough. 2 will only give you some delta pseudorange. For full coordiantes you need >= 4 sats.

just bitching

Re:Hello?

[pete-classic]

I don't use GPS, but I don't find it difficult to imagine some brain-dead outfit building a brain-dead unit that won't work outside of North America. I can imagine them doing this by design (i.e. "Going overseas? Buy our extra-expensive 'International' model!") or unintentionally ("Hmm, didn't think to handle values between the prime meridian and the date line going East!").

The question seems goofy at first, but I think it's reasonable in this light.

-Peter

Re:Hello?

[BJH]

Yeah, cause every uncharted village has a ready supply of alkaline batteries in AA, AAA and AAAA sizes.

Re:Hello?

[Anonymous Coward]

Actually, it is 230V +/- 10V tolerance.

Re:Hello?

[Uber Banker]

So to answer your question, of course GPS equipment can be used over there!

Well, sort of. Don't depend on GPS 100%.

• GPS can be turned off by the US government, and is done so regularly in hostile countries, and all the time in countries the US is at war with. So if there is the most remote possibility the US could get pissed off with the country you're in, don't do it.

• Making sense of your longitude and latitude means having a decent map in the first place. And while this argument is a bit circular given you'll be working in uncharted villages, at least carry a decent geological map.

Infact, a hi-tech solution is nice, but the low-tech is going to be orders of magnitude more use to you. As long as you have a basic geological/terrain map, it it quite simple to put an ink based red mark and write about something you find interesting. This will be more robust than:

• having expensive high-tech in extremely poor areas (a $100 (US retail price) piece of GPS equipment could probably be sent for much more in an area where annual incomes are significantly less than $100),

• Potentially rugged conditions: laptops dont take easily to 2 foot deep potholes every 5 metres on rugged roads when travelling on the 4x4. They certainly have an aversion to mud or dry earth should you drop it. 100% mission over if relying on standard (non-army standard) tech.

• Abstraction from a real scenario. It sounds like you're interacting with real people in a very human way: interact with them on as personal basis as possible, don't abstract yourself (your perception of them, or their perception of you hiding behind a screen) as that, on a 1-2-1 basis, could only be negative.

• Carry a weapon. I'm English, not a gun-nut Texan (no offense), but if going into a potentially hostile environment, don't carry it around when meeting people for the first time, but keep it discretely to hand when travelling.

As for the GPS equipment? Take 3 hand held sets, tested to be rugged for terrain use: carry 1 yourself, 1 for your partner (incase you get seperated), and 1 spare in your vehicle if yours gets over doused in mud.

On all the above, I assume you're planning a reasonably independent trip, with 1-2 guides, for around 3 months. If you're going in a party of 20 with masses of guides, well much could be unnecessary.

Re:Hello?

[Locke2005]

I call bullshit. My wife is from Sierra Leone (in West Africa), and she says American appliances plug in and work just fine there. Of course, electrical standards do vary from country to country, so your mileage may vary - check with someone from that specific country. Plus, don't most portable GPS receivers run on replacable batteries, not off of AC adaptors?

Re:Hello?

[Anonymous Coward]

actually, the best solution is to ask the spooks over there to send you the maps... :P

Re:Hello?

[AKAImBatman]

1. Different countries run different power. There are quite a few countries in Africa.

2. Quite a few modern pieces of electronic equipment already contain the necessary transformers to work in different parts of the world.

3. IT'S A JOKE! WHERE THE HECK IS YOUR SENSE OF HUMOR?

Yeash. You'd think the whole explanation of GPS as a setup would have tipped people off.

Re:Hello?

[Colin Smith]

"Thanks to the precision and accuracy of modern electronic hardware, this calculation can be accurate to within 20 meters or less."

The Ordnance Survey mapped the British Isles to an accuracy of less than 1 metre, top to bottom in 1935. Modern electronic hardware doesn't sound quite so accurate or precise when put into that kind of context.

Re:Hello?

[jabuzz]

Actually no they didn't, much of the rural area is out by up to 50 feet due to a mistake in the calculation, and it considered to costly to fix the mistake.

Re:Hello?

[ncc74656]

They use 220V AC and we use 110V AC. Where do you think you're going to find a charger? You need to get yourself a step down transformer, or you'll never be able to charge the equipment!

Then again, if your GPS receiver is bus-powered (like this one) and if your notebook comes with an auto-voltage power supply (99% of them do), all you'll need for it is an adapter to go from an American plug to whatever you need where you're going (like this, which is supposed to adapt to nearly anything).

(There's a fair chance you'll need transformers for some of the other gadgets you might bring along, but your computer and GPS receiver probably aren't among them.)

Re:Hello?

[Locke2005]

Different countries run different power. There are quite a few countries in Africa. Yep. Which part of "Of course, electrical standards do vary from country to country" did you not understand?

Re:Hello?

[Anonymous Coward]

And every uncharted village has power outlets he can just plug into.

Re:Hello?

[bosewicht]

Actually I do a great deal of training and collecting data using Trimble and our resource grade is accurate to a meter and our survey grade has sub-centimeter accuracy. So a great deal less than 20 meters. "Yeash, what are they teaching you kids these days?"

Re:Hello?

[rworne]

They work all right, but depending on the model you might need to fork over extra money for the maps. You get the maps either on disc as a separate purchase, or they are already on the unit and need and unlock code.

Simple Lat/Long models without mapping work fine though.

Somehow I doubt there will be maps of undeveloped countries. One word of warning though - GPS are illegal in some countries. I would check before bringing one.

Re:Hello?

[RobertLTux]

easy way to fix 1 Rechargeable batteries (have a few sets) 2 DC based charging unit or 2 Hand/foot crank based generator 3 local currency

Re:Hello?

[grcumb]

I work in remote, undeveloped countries (doing IT, if you can believe it) and I can confidently say that your biggest problem is going to be power.

Do yourself a favour and:

1. Make sure that your GPS runs on batteries.
2. Go out and get yourself 2-3 full sets of rechargeable batteries for every GPS device.
3. Buy a solar battery charger that is capable of charging a full set in less than 3 hours.
4. Bring lots of mosquito repellant. 40% DEET or better is recommended. That way you won't drop or damage the GPS as you flail madly at the bugs. 8^)

Re:Hello?

[Nogami_Saeko]

GPS can be turned off by the US government, and is done so regularly in hostile countries, and all the time in countries the US is at war with.

It usually isn't turned off. There are a lot of soldiers that carry/use civilian GPS units because the military units, while capable of being run over by tanks, bombed from above, and submerged to the bottom of the ocean SUCK when it comes to user interface and ease of use. Think user interface from a VAX and you'll be in the ballpark.

And now that selective availability is off (even in war-torn areas), there's no huge benefit from using the clunky military versions.

(now, if the military found that the enemy was using GPS to deliver bombs and such, of course they'd turn it off, but that's not how the vast majority of US encounters are conducted these days - it's fighting in the streets and suicide bombings which doesn't really require any form of GPS).

N.

Re:Hello?

[Bwah]

Step down? Bleh! Look carefully your equipment before bothering. I was suprised to find that the majority of my electronics are rated from 120 all the way to 240. (Canon stuff, fuji stuff, toshiba stuff, ipaq charger, etc.) You just need an adapter for the receptacle style. This has served me well for several asian countries, you just need to be careful when you buy your gear.

Now for the freaks on different freqs, you may need to start worrying about serious adapters. Then again a lot of gear is OK with 50 and 60Hz. Read all that little fine print on the power supplies.

(Besides, you should be using a solar charger for you GPS and laptop while in the field. Takes all the worry out of it.)

This sounds like a cool project. There is a ton of existing free GIS software to support it. If you do end up on windows, avoid Delorme. Their GPS gear is alright (nothing wonderful), but their software is pretty awful.

Re:Hello?

[Colin Smith]

You'd better phone the RAF before someone gets themselves killed then.

Re:Hello?

[Mr2cents]

Where is this so called "globe" and is it a part of the USA?

Re:Hello?

[AKAImBatman]

Which part of "It was a joke" did you not understand?

Re:Hello?

[Mr2cents]

> now, if the military found that the enemy was using GPS to deliver bombs and such, of course they'd turn it off,

I wouldn't turn it off, I would re-route it 8-)

Re:Hello?

[sapgau]

Solar battery chargers:
Are available at Canadian Tire

Re:Hello?

[sapgau]

Technically speaking you need 3 but the GPS gear needs to keep track of the fourth one when one of the 3 disappears over the horizon.

That's why it is very difficult to get GPS working in between tall buildings. Unless you have a repeater nearby for error correction.

Re:Hello?

[Moofie]

They have the sun in Canada? Who knew?

Re:Hello?

[sapgau]

Illegal?

By whom? The US army?

Please clarify!!

Re:Hello?

[Moofie]

Your full coordinate fix is in four dimensions: X, Y, Z, and time (since most handheld GPS units don't have an atomic clock in them). You need four satellites to precisely fix that location.

You can get less accurate fixes with fewer satellites because most units will make (pretty good) guesses and estimates, but you need four birds for a precise fix.

I think.

Re:Hello?

[Anonymous Coward]

Do you know how much power those waste. You yanks spend twice as much on power as you should! Heck, even leaving your TV plugged-in just so you can be lazy and use a remote to turn the TV "on" wastse watts of power (now times this times your number of DVD/VCR/TV/Computers/Monitors/etc that are not on a power switch that you actually _turn off_. Over a year, it really adds up!

Re:Hello?

[spewey]

Some GPS equipment does offer sub-metre accuracy. The Trimble unit I used at my last government job was beacon-corrected and offered 2cm accuracy when at least four sats were visible.

Re:Hello?

[sapgau]

You are correct, I found this on sciam.com:

"Further assume that a GPS receiver on the ground can measure the distance between a receiver and a satellite for at least three satellites at the same time. By defining the receiver location with three coordinates, such as latitude, longitude and height, one can readily write three equations that relate the three distance observations to the known coordinates of the satellites and the unknown coordinates of the receiver."

But since distance measurement needs to time how long the signal travels to earth, we need an accurate time measurement...

"The complete position determination of the receiver consequently requires four unknowns: the receiver clock error and the three receiver coordinates. Measuring distances to at least four satellites allows one to set up four equations that can be solved for these four unknowns"

How do GPS devices work?

Re:Hello?

[Anonymous Coward]

GPS can be turned off by the US government
Incorrect, they can add a lot of noise one of three (?) satellite signals thus diluting the precision to about 10 meters. They cannot turn it off.

and is done so regularly in hostile countries

You don't know what you are talking about. GPS signal cannot be toggled on per-country basis. You should really check your information before posting bull like this.

Re:Hello?

[rworne]

Illegal meaning the country being visited might consider a GPS to be "military equipment". The US and most if not all Western countries don't care, but 3rd world countries may. Checking with the local consulate of the country being visited should clear the matter up.

Check here.

Re:Hello?

[Anonymous Coward]

> of course GPS equipment can't be used over there!

No, you'll be fine. Just get a long enough power cord.

Re:Hello?

[ErikZ]

Beacon-corrected?

Doesn't that mean there's a local antenna who's position is known *exactly* and the GPS is using that as a reference?

Not too useful in undeveloped countries.

Re:Hello?

[thelost]

I agreed totally with your assessment up to the point where you said "carry a weapon". What in all names of holy would the point of that be? If you're looking for a good way to get yourself into trouble in an African country I could think of few ways better than taking a fire arm, or similar around with you.

Re:Hello?

[spewey]

Good point, unless the beacon antenna was very tall.

Re:Hello?

[3dr]

Here's the geometry of the situation:

Three satellites solve the lat,lon and time delay unknowns, giving you a 2D position (no elevation). Your position is actually ambiguous because two points satisfy the equations. One is on the ground of course, and the other is the mirror image out in space (relative to the three satellite locations). To get 3D position information, a fourth satellite provides the disambiguating data.

The three satellites define a plane and a fourth satellite tells which side of the plane your position is.

Just another interesting way to think about it.

Re:Hello?

[petermgreen]

actually the universal voltage ones are almost certainly switched mode which tend to be more efficiant than traditional linear power supplies.

as for saying wall warts are ineffciant its probablly true in a lot of cases but you can't trust car adaptors to be all that efficiant either and the losses of distributing at 12V can really add up.

Re:Hello?

[Idarubicin]

Bring lots of mosquito repellant. 40% DEET or better is recommended. That way you won't drop or damage the GPS as you flail madly at the bugs. 8^)

Be aware, however, that DEET eats plastic stuff--so keep the concentrated stuff away from your GPS equipment, as well as any synthetic clothing and such.

Re:Hello?

[petermgreen]

most of the world is either 60HZ at arround 115V or 50HZ at arround 230V. so making a universal voltage input without also allowing for both frequencies would be kind of stupid.

Re:Hello?

[hjf]

yea or just plug the bare wires into the outlets. heh, silly americans with "blade" pins can't plug a bare wire right in like I do in my country. or did. now they outlawed round-pin outlets and we have oblique-blade :(

Re:Hello?

[Anonymous Coward]

Canada has the sunniest days of any country in the world. We get 24 hours of sunlight in the summer.

Re:Hello?

[zippthorne]

40% deed is 60% alcohol. Is it the deet or the alcohol that wrecks the plastic stuff?

as an aside: the alcohol is now known to aid in the absorption of the deet, so it actually doesn't make sense to cut it with alcohol anymore. Of course you were putting the deet on your clothes not your skin in the first place right?

Re:Hello?

[rnturn]

``I agreed totally with your assessment up to the point where you said "carry a weapon".

Yah, that was pretty wierd. Wonder how you'd get in out of the U.S. let alone into your destination country.

Actually, if you need an armed escort, a few of the countries in Africa will arrange to provide you with one. At least that was the case when my sister was over there a few years ago assisting a classmate on a project to track rhinos (by collecting their, um, ah, droppings). The govt. provided an escort complete with AK47s to ward off poachers.

Re:Hello?

[StarsAreAlsoFire]

5. Get your shots. The night-time masquitos carry malaria. The daytime versions carry yellow fever. I might have that backwards, but really, does it matter when you contract which disease? ;~)

There are some pills that decrease the chances of getting malaria, and a shot for yellow fever (two shot series, if I recall correctly). Malarone is what I was provided for malaria 'prevention', and was told by a gal I met in the plane (who looked like hell, as she had just been in the clinic BECAUSE OF malaria) that it was the best (and she wished that she had had it).

Re:Hello?

[StarsAreAlsoFire]

Positioned conveniently at eye level when driving south.

Re:Hello?

[dickrichardv8]

The British probably started the survey in 1835. They think a 100 years is a short time and a 100 miles is a long ways. Maybe when they switched to meters they got that concept staightened out? What's the metric measurement for a year? Auhhh, Euro?

Re:Hello?

[Anonymous Coward]

Carry a gun?? are you nuts?? Only carry a gun if you want to be sure to get into trouble! If you DO not protection get a local to go with you - but NEVER carry a gun.

and to answer the initial question:
I have performed similar tasks in past, and the best solution is to carry a standard GPS combined with old fashion pencil and paper - and remember to use a pencil (and not a pen) if there is any change that you will get wet. You can carry a laptop if you want, but it's really not needed while in the field. And as someone else wrote leave it in the (locked) car while talking to locals.
You could also consider getting a satellite image (e.g. a Landsat TM image) to use as a background - but it depends on the scale of the mapping you are doing. Older images are available for free several places on the net.

Re:Hello?

[XchristX]

Best & most flexible way (I do this):

Get an ipaq or a Dell Axim or a sharp zaurus PDA with a cf expansion slot (if needed)

Install Familiar Linux or Openzaurus

Get a Holux GM-270 GPS Card (or anotherone here or here)

Install gpsdrive & enjoy

This way, no worrying about firmware incompatibilities, & if u buy an old ipaq h3600 from ebay your TCO can be less than $200

Re:Hello?

[sonictheboom]

The auto-switching adaptors are also good for (limited) protection from electrical surges. You are likely to get REALLY crap electricity (when you do get any power) and these come in handy. However I would recommend getting something else to protect your electrical stuff - locally made protection is likely to be good for this.

Re:Hello?

[tuxette]

5. Get your shots. The night-time masquitos carry malaria. The daytime versions carry yellow fever. I might have that backwards, but really, does it matter when you contract which disease? ;~)

A lot of African countries won't let you in unless you have a certificate of vaccination stating that you have been vaccinated against yellow fever at the very least (this is the only one I know of that is obligatory).

Re:Hello?

[Chris Hodges]

There are solar chargers easily available, e.g. (in the UK):

http://www.maplin.co.uk/module.aspx?ModuleNo=10438 &doy=15m7

2 sets of AA rechargeables should easily be sufficient (assuming decent sunshine - in West Africa - and from my experience of a Garmin ETrex)

Re:Hello?

[rikkards]

You know that is true. I had it happen to me when I was in Yellowknife... in November

Re:Hello?

[thelost]

that sounds more sensible then actually trying to arm and protect yourself, although I would still feel uncomfortable. I guess I feel uncomfortable with the whole notion of guns in any case, feeling they would be provocative in the first place, although I guess it would be important to have them if you accidently enraged a rhino :D

Re:Hello?

[cabra_nino]

actually the position of the satellite is irrelevant. only the distance matters. hence the need to see more than 3 satellites. Each satellite carries an atomic clock wich sends the GPS a tim signal. that is then compared to the time the gps has. The difference in the times multiplied by the speed of light (3*10^8 M/s) gives the distance of the satellite. Then once you know the distance from 3+ satellites you can locate youself on an ellipsoid using 3d trigonmometry. oh dear, I really shouldn't be allowed to post stuff like this should I? I'll go and lie down.

Re:Hello?

[ke5in]

GPS can be turned off by the US government, and is done so regularly in hostile countries, and all the time in countries the US is at war with.

The last half of this statement makes no sense. Since the GPS system was developed by the US military to precisely deliver military assets, why the hell would they turn it off in a place where they would use it the most i.e. " in countries the US is at war with"????????? Do you mean TURNING ON Selective Availability? And I don't think they use SA that much now anyway because many of the troops are using commercial versions they bought for themselves. Even with SA on the GPS is still pretty useful (probably not for making precise maps, but definitely good enough to show Point A relative to Point B and the route in between when the distance from A to B is measured in miles or kilometers.)

Re:Hello?

[coachvince]

I've never been on a safari, gone to Africa (or any other nation outside of North America, I admit), and don't feel uncomfortable with the whole notion of guns. With that said, I think a fast getaway is better than trying to stop a pissed off Gelaendewagen (OK, so it's 5400 lb.s, a rhino tops out at ~5000; how about a pissed-off Toyota Tundra @ 4900 or so?) heading for you.
If you've never fired a weapon more than a few times when your life wasn't at stake, don't count on that weapon when your life is at stake!
Pray that you can get to your vehicle quuickly, and that it's top speed over the terrain you're on is higher than the rhino's!

Re:Hello?

[dubl-u]

Yeash, what are they teaching you kids these days?

Says the guy who flunked Politeness 101.

Re:Hello?

[briancnorton]

This is no joke. West Africa is a dangerous place, and the customs officials and a constant streams of wannabe revolutionaries carrying AK-47s will quite simply take anything that they want. A ruggedized portable GPS unit is something they will want.

Think concealable. You may be able to get a VERY inexpensive GPS with no bells and whistles (and no map) that they would look at and not know what the hell it was. You may also find that a lot of uncharted villiages want to stay that way for (legitimate) security reasons, and you might have to take covert readings. (it's your life) To be honest though, I have something of a hard time believing that you can't find a position of a city in Geonet

Re:Hello?

[authalic]

The intentional degradation of the civilian GPS signal, known as SA or "Selective Availability" in GPS terminology, was ended on May 1, 2000, by an order signed by President Clinton. The press release announcing the change included this statement:

Additionally, we have demonstrated the capability to selectively deny GPS signals on a regional basis when our national security is threatened. This regional approach to denying navigation services is consistent with the 1996 plan to discontinue the degradation of civil and commercial GPS service globally through the SA technique.

See the full press release. Call it "bull" if you want, but you really should also check your information.

Re:Hello?

[THEbwana]

- Don't bring mosquito repellant to Africa.
The stuff we've got here can kill elefants. Your repellant will merely badger the african insects into attack mode (and you don't want that).

Re:Hello?

[topham]

His statements are bogus.

Selective Availability has been turned off since the CLinton administration.

Selective Availability was turned off during the first Gulf War. (opposite of what he implied). (US military was using mostly civilian GPS units and wanted the improved accuracy).

There is no reasonable expectation that Selective Availability will be turned on again; there have been multiple demonstrations of methods to cancel out the effects of SA and as such it servers little purposes on a day to day basis.

It may be beneficial to turn on SA -if- someone were to launch a weapon at the United States (for instance). But even then, most weapons do not require the level of accuracy that the US military wants.

(The U.S. military wants to blow up strategic targets, while terrorists want to blowup anybody and anything that will get the noticed. (never mind they tend to use much better navigational tools than GPS units... people.))

Re:Hello?

[RockDoctor]

Illegal meaning the country being visited might consider a GPS to be "military equipment".
Very much agreed.
My first trip to the former Soviet bloc was to Azerbaijan, and I took my GPS and found it very useful for work out in the middle of some extremely flat nowhere. My second trip was just after the burglars had stolen my GPS so no toys with me that time. Which was just as well, because the area I was working in was a military restricted zone (I found this out when I got there; as normal) and there was already one Yankee doing hard time for being found in such an area with a handheld GPS as /prima facia/ indication of criminal intent.
He's lucky he didn't get shot (if he did get shot later, "Sorry" to the family, I didn't know. I was lucky, the dude wasn't. Or he was a spook and got his paycheck cancelled.)
Almost certainly the consulate will tell you that they don't know the local regulations for certain, and that your best course would not to take anything you consider may be suspect ; if you do actually need the device in question, then simply apply for an armaments importation license and see how far that gets you. [If they do it this way, they're not liable for you refusing their advice, OR they have to forward a known piece of bureaucracy to known people in their chain of command, and the responsibility for the decision goes back to the home country. Much safer. And easier.]

Re:Hello?

[Anonymous Coward]

Yah, that was pretty wierd. Wonder how you'd get in out of the U.S. let alone into your destination country.

You can unload, declare, and check your guns in at the counter. That's how you get a gun with you when you go on a hunting trip that requires air travel.

Re:Hello?

[Kadin2048]

Yes I think you can only get this sort of accuracy with some sort of enhancement system. There are at least two different enhancement systems out there, one is mostly for marine use and uses land-based beacon stations, the other is satellite based and uses two geosync birds over North America to transmit correction info to capable receivers. It's called WAAS (Wide Area Augmentation System) and a lot of inexpensive receivers are capable of using it now. However, that said I've never actually gotten a strong WAAS signal in any sort of treecover. Also it's not germane to this discussion since it's North America only.

If you want something that's going to work everywhere, you're pretty much restricted to plane-jane GPS service.

OT: But has anyone heard anything about the GPS-type system that the Europeans were talking about building a few years ago? I think there was a Slashdot article on it.

GPS works everywhere, even Africa

[nokilli]

And instead of rugged, think small. You can get a small GPS that you can plug into your laptop via USB for under $100US. Should outlast the laptop.

As for mapping software, if you truly want it to be useful, just save off the coordinates and wait until you get Internet access, then integrate with Google Maps using their recently released API and you'll be able to actually look at the villages from above, on your computer.

Actually, this is the perfect time to be doing what you're doing.

Re:GPS works everywhere, even Africa

[Anonymous Coward]

Great idea! Then you'll only need a fast net connection and a newish computer to read maps of poor african villages. I love technology! Paper maps are for technophobes and google-haters!

Re:GPS works everywhere, even Africa

[SeventyBang]

There are also hand-helds, attachments for PDAs, and practically anything else you can imagine.

GPS is one of the more common things used at the DARPA Grand Challenge last year and I have no doubts but what it'll be standard equipment this year as well.

______________________
http://indyrobotics.com/ 85d : 6h : 57m : 30s : 7ms

Re:GPS works everywhere, even Africa

[baadger]

Google Maps doesn't cover Africa (yet)

Re:GPS works everywhere, even Africa

[Buchenskjoll]

Google maps won't help much. Basically only the US is covered to a degree where you can actually see a village. Anc Africa is particularly bad.

Re:GPS works everywhere, even Africa

[aaron.rowe]

Actually you are unlikey to find any detailed maps of west africa, I have worked on extensive mapping projects in Nigeria over the last five years, and All our maps have to be created from expensive satelite photos or even more expensive air photos. The government has no coordination with regards organising this information and simply relies on World Bank stumping up the cash for new satelite photos or air photos each time an up to date map is required. It makes me sad to see such waste.

I'm not totally familiar with other west african countries but I think if you are expecting to easily find accurate digital road maps, state boundaries and cities then I'm afraid you will be extremely frustrated.

As for GPS equipment, we use Leica surveying devices but we have also had good results with Garmin. A particular problem is that there are fewer GPS satelites over that part of the world so that there is a larger error in the data. The Leica equipment allows us to calibrate a base station device to eliminate the error.

Re:GPS works everywhere, even Africa

[ckaminski]

Ummm, didn't the Shuttle and the SRTM just map the entire fscking planet a few years back?

Minus roads and some smaller dwellings I'm sure... it was JUST a topography mission after all...

Re:GPS works everywhere, even Africa

[Eunuchswear]

Why not get the Soviet ones from http://www.omnimap.com?

Re:GPS works everywhere, even Africa

[aaron.rowe]

'a few years back' being the operative. But where are these maps anyway? Every project so far we've consulted government and academic sources in Nigeria and obtained nothing but 4 year old satelite photos and mapping that WE did in earlier projects that has been leaked to the public domain. In Nigeria most maps available date back from around 1992 around the time of the most recent census and there has been a great deal of development since then. In Lagos entire districts have been razed to the ground and redeveloped, also new suburbs have been developed that were just swamps 5 years ago. Property Development in Lagos is I think comparable to Western Metropolises! This echoes development in other West African Cities. of course YMMV.

Imagine you want to construct a reservoir in a remote part of a city outskirts and then discover that an entire town now exists where your map shows nothing but abandoned farmland or swampland.

Re:GPS works everywhere, even Africa

[LWATCDR]

I would say think even smaller. Why have a notebook at all? Most inexpensive gps unit will save way points. Why take the notebook into the field if you don't have to? Take the GPS and mark each village as a way point. When you get back to your main location just dump the way points into a GIS system, Google Earth, or mark them on a paper map.

Re:GPS works everywhere, even Africa

[mikkom]

Satellite part covers the whole world so it will propably be VERY helpful in mapping.

Just zoom the below
http://maps.google.com/maps?ll=0.703125,15.996094& spn=75.480469,133.927734&t=k&hl=en

Re:GPS works everywhere, even Africa

[Kadin2048]

I gotta call you on the 'fewer satellites' business. It's my understanding that the GPS sats are a low-orbit constellation, 24 of them or so, and that each is constantly moving around the earth. Unless they were constantly maneuvering them, this makes it impossible for there to ever be more satellites over one location than over any other.

I guess they could put more at higher latitudes, if they thought that was where the demand was going to be, but that just doesn't seem consistent with the system design.

Maybe there's some other reason why you're not seeing as many satellites down there?

No

[smileyy]

does GPS equipment from the US work over there?

No. We made sure to send Africa very very degraded signals. How much does a meter of accuracy matter in a desert or jungle anyway?

Re:No

[Anonymous Coward]

Wow, mods suck so bad it's not even funny.

Hey mod, ever heard of sarcasm?

Re:No

[psychofox]

Actually, africa does not have augmentive correct signals. So in comparison to accuracy in the US they have signficantly degraded accuracy.

google for WAAS or EGNOS

Re:No

[BlogPope]

So in comparison to accuracy in the US they have signficantly degraded accuracy.

I seem to recall that its fairly simple to vastly improve accuracy of GPS by keeping it still for an extended period (days and weeks perhaps). Since the "noise" drifts around your precise location, after an extended period you can average out the noise and get an answer accurate to inches if I recall. Geologists use this trick to detect movement of tetonic plates of less than an inch, though I'm sure they are far more patient than the questioner...

Cover your eyes...

[Anonymous Coward]

...turn around 3 times and walk in that direction.

Obligatory Fanboy Response

[fembots]

Google Map, Google Earth or Google Satellite?

Wait, and it'll be built.

Re:Obligatory Fanboy Response

[Fishead]

Oh yeah, Google earth.

I was just playing with this last night. It is frikken SWEET. I have installed some Marine Navigation camera's around the world, and was able to even find some of the ships that I worked on. I was blown away how cool it is. For $20 you can buy the plus version that allows you to Sync with your GPS. This is TOTALLY the way to go. The only drawback is that the entire earth isn't imaged to the same Resolution. Some of the places I have been are only clear from about 20,000 feet up, where as others are clear to 300 feet up. Some co-workers could identify their cars parked in their driveways.

Google Earth is very worth checking out. Plus Google is just cool.

Re:Obligatory Fanboy Response

[Locke2005]

Good suggestion, but neither the Google Map nor the Google Satellite data base appears to have enough resolution to find a specific town in West Africa, let alone a specific street. Google Satellite only has high-res images of the most populated areas of the United States; I know because own property that there are no high-res images available for.

Re:Obligatory Fanboy Response

[ezzzD55J]

I was just playing with this last night. It is frikken SWEET.

Google Earth is very worth checking out. Plus Google is just cool.

Awesome comment. I presume by cool, you mean totally sweet. But.. Does Google flip out and kill people?

;-)

Re:Obligatory Fanboy Response

[kinzillah]

And plenty other places. I've bothered looking at London and Tokyo. I am sure there are others.

Old School

[darth_MALL]

Get Lewis and Clark out there. It's not like they're busy these days.

Re:Old School

[schon]

This might come as a shock to you, but they're not real; they're fictional characters popularized by a television show.

Oh, and you misspelled her name; it's Lois, not Lewis.

Watch out...

[Anonymous Coward]

That they don't nick your GPS from you in Africa...

GPS Software

[archaic0]

I personally use Delorme's Street software to get around here in the states and it's been pretty good. I know that wouldn't work your purpose, but delorme also makes some great GIS tools. Their page doesn't elaborate on whether it's all for the US only though.

As for the hardware, I'm pretty sure that any GPS will work anywhere to give you lat/lon whether you've got a local map or not.

Compass

[centauri]

Even fairly basic GPS receivers come with built in compasses. Never hurts to have a back up though.

Re:Compass

[Pollardito]

compass, graph paper, No. 2 pencil (if it's a small village, you can get away with one of those golf scorecard pencils for more portability)

Re:Compass

[centauri]

Nah, a hex grid is better. Movement and spell areas are more realistic that way.

For reference see: http://www.giantitp.com/cgi-bin/GiantITP/ootscript ?SK=175

Don't take your GPS "everywhere"

[jaredmauch]

I travel in the US with a GPS in my laptop bag (Garmin GPS V), but depending on where you travel in the world, you may want to insure it doesn't violate any local laws. For example in (don't mod me funny) Ex-Soviet Russia it is illegal in most cases to have GPS equipment. You can be thrown in jail and it may not be pleasant.

Re:Don't take your GPS "everywhere"

[Otter]

I'm not sure why two mods decided this was Funny. It's something I certainly hadn't thought of, and it's definitely something that the questioner and any other traveller ought to keep in mind.

The trouble spots in West Africa tend to have too little law rather than too much, but if his girlfriend is in a country with fighting going on, it would definitely be worth her while to ask what the local militia might find objectionable. And stable but paranoid countries like Nigeria might well have laws similar to the Russian one.

Re:Don't take your GPS "everywhere"

[Anonymous Coward]

I'm not sure why two mods decided this was Funny.

Because of this choice line of his:

For example in (don't mod me funny)

So the mods (being an ever predictable bunch) decided to go against his wishes and mod him funny! Hilarious, isn't it? A real knee-slapper!

Re:Don't take your GPS "everywhere"

[centauri]

In Soviet Russia, satellite locks on to YOU!

Re:Don't take your GPS "everywhere"

[dtungsten]

I'm not sure why two mods decided this was Funny.

I'm sure it was because they thought it would be funny to do so, given that the commenter didn't want to be modded funny.

Re:Don't take your GPS "everywhere"

[JoshRosenbaum]

Hilarious, isn't it? A real knee-slapper!

I blame it on getting off work. At that point you're just begging for something to be funny and you'll accept anything. ;) For example I laughed at what you said. Then again, making fun of someone else's crappy joke is a true formula for funny, right? :) Too bad I have no mod points. ;)

Re:Don't take your GPS "everywhere"

[budgenator]

more likely find he local militia might find it desirable.

Re:Don't take your GPS "everywhere"

[Anonymous Coward]

ENSURE not INSURE. Sheesh. Sell the GPS and buy yourself a dictionary!

Re:Don't take your GPS "everywhere"

[KevlarTheSleepinator]

was the parent modded funny because he said not to?

heh.
if so, here's a comprehensive guide i've written on how to word your posts here on /. so that you get the moddings you want:

Step 1. for any troll/flamebait/whatever posts that could be modded down, say "i'll probably be modded troll/flamebait/whatever for this, but..." to get modded the opposite.

Step 2. for any other post that might just fall into obscurity, say "dont mod me funny/interesting/informative/insightful/etc" to get modded what you said.

Step 3. ???
Step 4. Profit!!

Re:Don't take your GPS "everywhere"

[jaredmauch]

yeah yeah, anyways, i'm guessing metamod will likely 'fix' this after a bit, if not, it's just slashdot afterall :) I am sure that the orig poster will read it and check, the rest of the folks deserve what they get, i tried to help.

Re:Don't take your GPS "everywhere"

[KevlarTheSleepinator]

oops, i forgot to ask everyone to not mod me funny on my parent post

Re:Don't take your GPS "everywhere"

[Anonymous Coward]

It is also illegal in Syria. When entering Syria via land, the frequently (unless you pay the officer) seize video cams and cameras. Taking a photo in central Damascus near a military building will get you arrested. If they see you holding a Palm Pilot, you are history. In Russia, if you go to prison, there are ways you can buy your way out, but in Damascus, the Syrians will take your money and torture you afterwords.

Re:Don't take your GPS "everywhere"

[Stauf]

Does that work? I wouldv'e though better of the mods (please don't mod me insightful).

Re:Don't take your GPS "everywhere"

[ockegheim]

Gee, I hope I don't have to meta-moderate this one...

It should work

[CKnight]

unless you get the discounted Global -except West Africa- Possitioning System.

Re:It should work

[Anonymous Coward]

The question is legitimate... try taking your Sirius satellite radio to Africa and you'll quickly find out what the word 'horizon' means to satcom. It could be possible for a reciever to only seek the satellites in geosynchronous orbit over North America.

Re:It should work

[identity0]

Cut him some slack, Floodimus (npflood@alumni.cedarville.edu) is obviously a graduate student. He can't be expected to use common sense or logic, he's college educated.

Re:It should work

[ckaminski]

Too bad GPS satellites aren't in geosynchronous orbit, but polar orbits.

Rugged GPS units

[bobcat7677]

To my knowledge, Trimble makes the best/most rugged GPS units available. They supply the military. They also have specialized equiptment for mapping. Here is the linkage: http://www.trimble.com/

There are also armored/waterproof cases and what not you can get for the more common off-the-shelf units.

As for software and compatability...I'll defer to someone else to post on that.

Re:Rugged GPS units

[Jurisenpai]

I can answer that! I just might work for a Trimble dealer! :)

For mapping, I recommend the new Recon GPS Card Edition. It's under 2K, TerraSync software included, and gets autonomous accuracy of 5-10 meters. The Recon is also rugged, and can withstand drops, mud, sand, floods, etc. If you're worried about charging it, you can buy a car charger for out in the field as well as an international charger that has adapters for quite a few countries.

Trimble is running some really good specials right now on Recons; call your local dealer and see what they can do.

Re:Rugged GPS units

[Illserve]

Or.... check this out:

you buy 3 or 4 magellans for the same price.

And what is he going to do with a trimble box unit? Plug it into his... palm pilot? Yea, that'll last longer than a Magellan or Garmin.

Re:Rugged GPS units

[Mik3D]

For the sake of argument you might also consider the Thales Mobile Mapper which lists for $1750.00 with the post processing option. It is an excellent stand alone collection device with the simplicity of an embeded OS.

Re:Rugged GPS units

[qyiet]

I was told a funny story about how trimble got that contract. Please correct any errors I make in the retelling

The GPS Satilites are run by the US military. So as other people can't (easily) use them for *very* accurate positioning the military throw a deliberate error into the system. That error used to be much bigger than it is now.

The Gulf war was the first time they deployed a LOT of GPS units to troops, more than they could build in house. So they got the extra units from trimble. Now the trimble units couldn't fix the deliberate error that the military threw into the system (because it was a super secret), so for the duration of the war they turned the error off.

Out in the feild it was quickly discovered that the trimble GPSs were much better than the ones the military had built themselves. So some non-disclosure agreements later trimble had the algerithm for the error, and now sell their units to the military was well as the rest of the world.

-Qyiet

Re:Rugged GPS units

[Anonymous Coward]

The Recon is nice but it is not the best choice. I have managed to break a Recon with a GPS card in it. The compact flash expansion slot for the GPS card/antenna is a weak point, drop it once and it's done. Recon's are durable, but once that card is hanging out the top of it...

I'd use a Garmin 60cs, it's damn solid and has decent quality maps for most places. If iI had to homebrew my maps I would just plug the garmin into a laptop and use one of hundreds of different applications.

Re:Rugged GPS units

[Anonymous Coward]

Personally, I think you should by the D&D Player Handbook. It comes with a CD with useful tools for character creation and mapping. That way you can even populate the villages if you want. Besides, they have all stock graphics for an evil temple that most other mapping software avoids.

2 things

[Rosco P. Coltrane]

(does GPS equipment from the US work over there?), field equipment, mapping software etc. I use both PCs and Macs

1) GPS equipment, bought anywhere in the world, works anywhere else in the world, since GPS satellites cover the entire globe

2) All you describe is fine and dandy, but it seems to me that you're forgetting one crucial part of it: power supply. In the Middle of Nowhere, West Africa, you may not be able to find wall outlets everywhere to connect your laptop to everyday. What's more, if you do find power, your laptop might not like it (voltage spikes, bad frequency...).

So my suggestion is that you start designing around your power supply. Solar? Generator? how to conserve power? PDA or laptop? what size battery to you expect to need? etc etc... all that depends on the exact application.

Re:2 things

[Chuckstar]

I would imagine he has some mode of transportation. My laptop works just fine plugged into my car. I think you're overreacting a little bit.

Re:2 things

[temojen]

Another thing...

Most countries don't look too kindly on foreigners with computers, GPS recievers, compasses, maps, binoculars, and cameras.

Re:2 things

[t_allardyce]

I think the more realistic approach would be: several spare notebook batteries and a surge/spike protector plus a cigarette lighter adaptor. Plus GPS accuracy varies accross the world and might be intentionally reduced in some areas so he should probably have some way of checking it with existing maps.

Re:2 things

[PortWineBoy]

I'm guessing that's a joke? Take away the compass and you'll probably find more and more people travelling with these items every day.

What countries in particular are you talking about? I've travelled a bit around the globe and taken everything except the compass (the GPS served that purpose) on every trip. Obviously in the Third World these items are susceptible to theft...

Re:2 things

[Ricdude]

For solar charging of your laptop: http://www.realgoods.com/renew/shop/product.cfm/dp /1000/sd/1006/ts/3415278

They also have solar battery rechargers and rechargable batteries for the GPS unit.

I would think the key to what you want is something with plenty of memory for storing the village locations and, perhaps more importantly, the routes to access them.

Also, some reading material might be useful depending on where you plan on going. (http://www.amazon.com/exec/obidos/tg/detail/-/006 0011602/qid=1121378747/sr=8-1/ref=pd_bbs_ur_1/103- 2873278-2601459?v=glance&s=books&n=507846). Usually includes when the local rebels prefer to lay their mines, how to bribe your way out of various situations without actually offerring to bribe anyone, etc...

Re:2 things

[Anonymous Coward]

does GPS equipment from the US work over there?

All you describe is fine and dandy, but it seems to me that you're forgetting one crucial part of it: power supply.

What about solar panels? Does solar panel equipment from the US work over there?

Re:2 things

[jimi the hippie]

Obviously in the First World these things are even more susceptible to theft.

Re:2 things

[Anonymous Coward]

As someone pointed out in another post, Russia may not look kindly upon GPS recievers.

Re:2 things

[KarMann]

Good post, except for one minor thing (out of 2):

I would think the key to what you want is something with plenty of memory for storing the village locations and, perhaps more importantly, the routes to access them.

What you need for that, of course, is hard drive space, not memory, assuming you don't mean the computer's capacity to display all the data at once.

And, as alluded to in many other posts, you should probably pay attention to the manufacturer's specs for shock the drives can withstand, out in the field. Perhaps temperature and relative humidity as well.

Re:2 things

[Anonymous Coward]

If you are going to use a generator, think about getting a diesel generator. Diesel is available everywhere. Also, you need a Furman Power Conditioner. In fact, it would probably be better if you got a SKB transit case and shipped everything in one transit case that has wheels. That would be ideal.

Re:2 things

[Anonymous Coward]

countries like, i dunno.... greece ?

and in 3rd world countries they are subject to more than theft: you will have to bribe every border crossing office and staff, on the way in, and on the way out.... or it's "strip to your undershorts, love monkey".

Southern Hemisphere GPS Usage

[webdan]

To use a GPS device in the southern hemisphere, (ie south of the equator) you have to hold it upside down.

Re:Southern Hemisphere GPS Usage

[cplusplus]

To use a GPS device in the southern hemisphere, (ie south of the equator) you have to hold it upside down.

I tried that when I was in Peru. I believe that technique works best when you walk backwards as well.

Re:Southern Hemisphere GPS Usage

[Anonymous Coward]

Some clarification is required here.

In the southern hemisphere, you still hold the unit the right way up. Sheesh, what are you people thinking??

However you must stand upside down or the positioning will not be accurate.

Re:Southern Hemisphere GPS Usage

[Anonymous Coward]

In Soviet Russia, the GPS turns you upside down!

why bother?

[Gothmolly]

is she doing these people a favor by mapping their villages out? Lets see, once they're mapped, they'll:
* have access to great UN Health Care, so that all their babies won't die of plague. Of course, they won't be able to FEED them all, so they'll either die of starvation later, or go to war with the neighboring villages for food
* be visited by the limosine liberals, the STD-carrying, raping UN peacekeepers, and their local thugs^H^H^H^H^Hgovernment, to pay taxes
* be able to present claims of 'need' on the wealthier villages, countries and planets around them

Seriously, let them stay anonymous, uncharted and undisturbed by the foulness that sweeps the rest of Africa.

Yes, this is a troll. But one man's -1,Troll is another man's +1,Insightful. What philosophy do you want to believe in today?

Fishy...

[Anonymous Coward]

Is the "girlfriend" in Africa a new take on the ol' "I have a girlfriend. She lives in Canada...?" I mean, this is slashdot.

Re:Fishy...

[Anonymous Coward]

"Is the "girlfriend" in Africa a new take on the ol' "I have a girlfriend. She lives in Canada...?" I mean, this is slashdot."

Actually it's not so fishy. He is alumni of Cedarville.edu (check his email address) which is a pretty hardcore christian college. After graduation, many of the alumni go on missionaries to Africa in attempt to covert as many people over to Christianity as they can. Venturing into new villages to find new "crop" i'm sure is commonplace and so the need for maps to pass on to the other missionaries. He probably does have a religious girlfriend over there.

220V

[HermanAB]

Aaaaah, geeezzz! You should not have told him. Now you spoiled all the fun when he would plug his brand new gear in... Actually, a Magellan handheld GPS will work fine anywhere in the world, provided that you have spare batteries, or a charger for that country. However, I would start with a good set of satellite photos - chances are that the villages are on the photos, in which case, you'll have more time to spend with your girlfriend...

Re:220V

[centauri]

However, the Magellen Explorist 200 (or whatever number the blue one is) that I bought, lost compass functionality less than a month after I got it. I returned it and bought the Garmin eTrex C for twice the price. It's upgradeable, and links with a computer via USB, unlike the Explorist (and unlike the B&W version of the eTrex, which uses a serial connection for some reason).

Re:220V

[Cromac]

What are the chances that Google already has it mapped?

Re:220V

[mpiktas]

Slim.

From Google Earth - Common questions:

3. Are there cities covered in detail worldwide? Or just in the US?

The whole world is covered with medium resolution imagery and terrain data. This resolution allows you to see major geographic features and man-made development such as towns, but not detail of individual buildings. Additional high-resolution imagery which reveals detail for individual buildings is available for most of the major cities in the US, Western Europe, Canada, and the UK. 3D buildings are represented in 38 US cities (the major urban areas). Detailed road maps are available for the US, Canada, the UK, and Western Europe. And Google Local search is available for the US, Canada, and the UK.

So even places with maps are not still mapped by Google.

Power? Storage?

[Bastian]

My first thought isn't what equipment would be the most fun or powerful, but what equipment will work. How reliable will electricity be in the area you are going to be mapping? Since you describe these areas as uncharted, ,y guess would be "not very," so don't expect that Mac to always be available to you.

Now what are you going to do without that laptop? You're going to need a GPS device that runs for a *long* time on batteries, or you're going to need to bring a crate of batteries where you go. You're also going to need something that allows you to save and tag all this GPS data so that you can decipher it when you do get back to a computer.

Get that figured out, and if you have any money left over, THEN you can start thinking about buying that copy of ArcView.

Re:Power? Storage?

[gardyloo]

My first thought isn't what equipment would be the most fun or powerful [...]

He says he has a girlfriend. My first thought WAS.

Re:Power? Storage?

[flyingsquid]

You're also going to need something that allows you to save and tag all this GPS data so that you can decipher it when you do get back to a computer.

Pencil and paper works fine for recording GPS coordinates, or you can just save your points in the GPS unit itself(entry-level Garmin units save several hundred data points, high-end units can hold thousands). Probably both would be good in case someone rips off your GPS. The interface on the cheap (~100$) Garmin units is annoying and poorly designed (you end up doing everything with four buttons), but it works for letting you name and save your points. Even entry-level units are really accurate (down to 15 meters or less), which I assume is more than enough if you simply want to put a village on a map.

When I was in Madagascar, bigger towns had batteries for sale in the markets, though they were of inferior quality, so you're best off bringing a bunch of your own. Also, GPS units really tend to suck power pretty fast, to conserve power you're best off turning it on only for a few minutes at a time- when you need to figure out which direction to head, and when you want to mark a point. Best thing to do might be to borrow one and take it out hiking a bit and see how it works.

If you've got a ham radio license

[mstyne]

APRS could be your new best friend.

Re:If you've got a ham radio license

[Anonymous Coward]

Of course, an American ham radio licence won't do you much good in Africa ;)

Re:If you've got a ham radio license

[Anonymous Coward]

It will if it's a country we have reciprocal privilige agreements with (but I don't believe there are any in Africa). A ticket from the appropriate country will still be just as good.

GPS in West Africa

[Anonymous Coward]

My girlfriend lives and works in West Africa
Were you the guy in high school who had the girlfriend who went to "another school" and no one had ever met?
Just joshing....

for some inspiration...

[geminiDelta]

try reading The Mapmakers by John Noble Wilford. An excellent history of cartography from the Egyptians to today... It will either inspire you or make you realize you're taking on a bigger challenge than you realize!

Watch

[Anonymous Coward]

Buy an GPS watch!

No power problems!

Re:Watch

[Rosco P. Coltrane]

Buy an GPS watch! No power problems!

Oh yeah? and what happens when it stops? do you rewind it?

Don't.

[Anonymous Coward]

Forget it. It won't last. Long distance relationships never do. She'll only break your heart.

GPS hardware reviews @ http://gpsinformation.net/

[digitaldc]

http://gpsinformation.net/

Hope this helps

most rugged stuff you've used?

[Anonymous Coward]

AK-47. Accept no substitutes.

Best GPS for travelling

[codell]

If you're looking for something compact, rugged and with a decent screen, the Garmin 60CS would be a good choice. I've had mine for two years and have put it through hell - backcountry hiking, sailing, flying, dousing it in mud, beer and water (it's waterproof.) The screen is small but readable in just about any lighting condition (great in direct sun!)

My only complaint with Garmin is the expense of the maps, but I've yet to see much serious competition as far as hardware goes.

Re:Best GPS for travelling

[Tran]

and 2AA batteries easily last for 12 hours. At least on my 60C ( no S ) they do.

Use satellite images

[MathFox]

My suggestion is to buy some good-resolution satelite images (a few meters) and have your girlfriend draw her map using that. You can use a GPS receiver to calibrate the satelite image to actual coordinates.

I think that a handheld (Palm) would be more convenient for measurements than a laptop. Handheld and GPS receiver do fit in your pocket and they have less moving parts than a laptop.

Re:Use satellite images

[Illserve]

Buy an Integrated unit!!!

You do not want to be walking around in the wild with a palmpilot and a GPS unit stuck on the top of it.

Magellan and Garmin make the perfect products for you, USE THEM.

It's tough
It's water proof (at least more than a pda)
It's battery powered with double A's that you can conceivably find even in underdeveloped nations
It has a huge pile of memories and maps already integrated.

Now granted, African maps may not exist, but at least you can put in waypoints for important places and navigate between them.

Just... whatever you do, do not try to trust your computers or pdas. You'll end up paying more in the end, and for a solution that is fragile and needs line voltage or car battery to charge.

I have beat the holy living shit out of my Magellan Meridian for 2 years now and it still works like a champ, and for a price of about $150.

Re:Use satellite images

[LnxAddct]

I hope when you said draw, you didn't mean draw with a pen or pencil kinda draw :) Anyway, I recommend he just grabs a gps receiver for laptops, a laptop with a car adapter, and the Pro version of Google Earth. Hook up your GPS receiver and just walk around the village, Google Earth will make the map for him and it has pretty high-def satellite images. If the village is so small that satellite images are not close enough, just use the software that came with the unit or one of the many open source GIS programs to automatically map it for you as you walk. I'd recommend using Google Earth though, as the map will read much better with terrain and semi-recent details of the village roads and trails. You'll also be able to tell if you've missed any big landmarks or anything.
Regards,
Steve

Specific African info about GPS & Mapping

[jan de bont]

Good generic GPS info plus specific tips for mapping in Africa to be found here: http://www.gpswaypoints.co.za/

Re:A couple of answers

[Anonymous Coward]

The G in GSM also stands for Global, and AFAIK you can't just walk to another country and use your phone if your company doesn't have roaming agreements with the local companies. Also at a lower level, you need a dual (900/1800MHz) or triple (900/1800/1900MHz) band cellular to be fully compatible with all Global System for Mobile Communications networks.
I'm not saying GSM works the same way as GPS, I'm just saying that Global doesn't necessarily mean that the it works or is compatible with the rest of the Universe.

But is she hot?

[rafael_es_son]

I mean, I hear it's quite hot in Africa this time of year.

Cartography

[GCP]

Don't invent the field of cartography from scratch. Study it before you leave.

I don't know what "mapping" means in your case. Are you trying to show where each village is or are you trying to create street maps of the major towns? In any case, find out what maps already exist, then go get yourself the best satellite photos you can find, and when you get there, prepare to rent small aircraft for some aerial photography. Trying to map West Africa on foot from scratch with a pocket GPS device would be a fool's errand.

And be VERY CAREFUL. People who make maps are often considered spies by people who carry guns. You'd better be very sure you know what you are doing and have the necessary permission from whoever (official or unofficial) controls the guns in the region you are mapping.

Re:Cartography

[TedTschopp]

Also it should be noted that in certain countries it is illeagle to possess maps over a certain level of detail. Make sure you understand the laws of the country you are going to, and work within them. If you don't then you will not only be considered a spy, you might legally be a spy, even though your intentions are noble or benign.

Re:Cartography

[HermanAB]

Laws? It is Africa - they don't have laws, not in the sense a European softie is used to anyway. The only law is to be very polite to the guy with the AK47... ...and don't try to pet the animals...

Re:Cartography

[Anonymous Coward]

Trying to map West Africa on foot from scratch with a pocket GPS device would be a fool's errand.

He's going to visit his girlfriend. This is her way of keeping him busy when she's working and/or provide a noble sounding excuse to buy new toys when what he really is going to be doing is eating, drinking, and shagging.

Re:Cartography

[Rac3r5]

in Soviet West Africa chars map you.

Re:Cartography

[ninjagin]

Aye. Good points.

The plane charter will be of great assistance in contextualizing what you see on the ground against what your sat maps show. You may also be able to spot commonly used trade routes, animal migration routes and footpaths that don't show up as readily as established roadways. Many maps are not able to provide these more subtle details out of concern for clutter or overdoing the scope, but ethnographers, anthropologists and biologists can appreciate it -- especially in areas they don't get to very often. Getting a bush plane is a great piece of advice.

Stuff I'd add:

Creating a street map of any towns you visit can be one way to meet a lot of people and enlist the help of locals. Be sure to leave a copy or two of the map in-town, and follow up by leaving copies at the nearest government office and university.

I'd also suggest affiliating yourself with a geographic society before you go. It may help garner some contacts when you get there (professors, government officials, etc.), and also a way to get some more locally-specific advice about where to go, what areas are most sparsely covered by cartographers/surveyors, etc. Contact the Interior Ministry. Contact the geography professor at the university. You may be able to get some assistance from students, and it may help you get any necessary papers or authorizations required to make the trip more problem-free.

If it's suggested that you hire guards in an area, get help finding some that are trustworthy, hire them and pay them well. This is one area where having some local gov't or university contacts ahead of time can really help.

It sounds like a blast. Good on ye and have fun!

Re:Cartography

[pete-classic]

"Do not pet lion with remaining hand."

-Peter

Why the fuck would you want to go to Africa?

[Anonymous Coward]

It's just like Atlanta, but without a Starbucks....

Re:Why the fuck would you want to go to Africa?

[Eunuchswear]

Well, the lack of a Starbucks is the reason.

Who the fuck would want to go to Atlanta?

Political considerations

[derdesh]

You should also be careful of the impression you make on local police or military personel. I don't doubt that many of them would be suspicious of an American (since you asked about U.S. equipment) wandering around with electronic devices to map villages or roads.

Never mind that if the military or intelligence agencies really wanted to know where things were, satellite images would be even more accurate than a cheap/rugged GPS. Many West African countries make it illegal to photograph airports, military bases, police stations and the like.

I'm not saying don't do it, just be careful who sees you. No reason to give excuses for an anti-western, self-important jerk with an automatic rifle to harrass you.

Re:Political considerations

[cayenne8]

"You should also be careful of the impression you make on local police or military personel. I don't doubt that many of them would be suspicious of an American (since you asked about U.S. equipment) wandering around with electronic devices to map villages or roads. "

You've got to be kidding....why would this bother them?

Re:Political considerations

[grcumb]

"You've got to be kidding....why would this bother them?"

A bunch of different coloured people speaking a foreign tongue wander all over your home town with some kind of weird sensing equipment that you've never seen before in your life.

If you can name one town in the USA where behaviour like that wouldn't result in phone calls to (and questions from) the local authorities, I'll agree that the GP was out of line.

But you won't. So no, he's not kidding. People in small towns are just like that.

Re:Political considerations

[I confirm I'm not a]

A bunch of different coloured people speaking a foreign tongue wander all over your home town with some kind of weird sensing equipment that you've never seen before in your life.
If you can name one town in the USA where behaviour like that wouldn't result in phone calls to (and questions from) the local authorities, I'll agree that the GP was out of line.

I was trying to share my wifi connection with a neighbour at about the extent of my access point's range. I was wandering down the street with a wifi-enabled laptop, when another neighbour - very irate - came out to ask what the hell I thought I was doing, logging details of his car?

This was in Glasgow, Scotland - one place where people are *not* that likely to call the cops, but rather sort the problem themselves (or get their mates to <ahem> sort it). Anywhere else in the UK, I'd expect people to call the police. Outside the 1st world, I'd expect people to call the army. People fear the worst when they see strange stuff - it's part of our basic fight-or-flight programming, even in leafy suburban Glasgow.

Re:Political considerations

[Anonymous Coward]

"leafy suburban Glasgow"

Eh? I thought Glasgow was all tenements, sectarian violence and bucky. Must be a different Glasgow.

Re:Political considerations

[I confirm I'm not a]

Eh? I thought Glasgow was all tenements, sectarian violence and bucky. Must be a different Glasgow.

That's a lie, ya bass, and ah'll chib ya if ye repeat it!

Seriously, Glasgow's a diverse city. Some of the tenements are actually nice (mine is!); when they were built (in the late 1800s) the "Corporation of Glasgow" spent a lot of money on them - I've seen friend's flats (rented) with marble (or at least good quality fake marble) fireplaces, etc. The sectarian part is all true - as it is throughout much of the West of Scotland, but the flipside is Glaswegians aren't particularly racist (except towards the English). And sectarian bigotry is limited to a few nutters - both the major football clubs and both the major churches have worked wonders in sidelining sectarianism.

Can't argue with the buckie, though. I went to work in Coatbridge once, early in the morning - 7:30 maybe - and saw neds with buckie bottles. Where do you buy wine at that hour? I can't believe it was left over from the previous night; that's not what happens with neds and buckie.

Re:Political considerations

[wdtj]

Gee, I have a photographer friend that was arrested just for taking pictures of buildings in downtown Minneapolis.

Best for your or your girlfriend to talk to someone in authority before you go poking around.

Be careful!!

[John Seminal]

My girlfriend lives and works in West Africa and on my next visit she has asked me to help her do some mapping of uncharted villages. I want to make this study really accurate

There might be villages that don't want to have their exact location well known.

Lots of these villages have been at war with other villages and tribes for a long, long time.

Many African governments are currupt, and would love to do ethnic cleansing.

Your wanting to provide accurate maps might do more harm than good.

I can just see some Diamond company in the USA, which hears about a new mine that had Diamonds at some coordinate. They then look at your map, and exterminate a whole village. It has happened in the past

This should be a map that only includes those who wish to be included. Don't force anyone on the map. Some tribe might decide to have you for dinner.

Re:Be careful!!

[Anonymous Coward]

Hmm...

Were you present at all these ethic cleansings all over the continent? Or was all this new found "knowledge" from your one of your CNN fed binges?

I'm African. I am in the United States and it gets really tiring hearing all these "corrupt, cleansing, wars" stories. Jesus! There was a bombing in London last week, you obviously watched it wherever you are. Now will you say there's a war there now? There are wars, like the ones in the middle east, yes but not all over the friggin continent!

Get the facts right before you make your comments. Take a trip over to Africa (which is actually made up of 54 countries and not a single entity like live8 would have us belive), observe, then you can sit on your three legged pedestel and say your favorite words - "corrupt, cleansing, wars".

Damm!

Re:Be careful!!

[Tiger4]

The parent message might be a little paranoid, but this is a real consideration. The former Soviet Union considered maps to be a weapon for almost this exact reason. Same goes for some of the Central American jungle wars in the 80s and 90s.

In any case, in addition to considering the GPS unit itself, consider the mapping software. Most people get software that tells them how to go places. You will need software that lets you build new maps. It has to store and lable many hundreds, if not thousands, of new points. Many of those points will need specific lables like "Intersection, First and Main" or "Junction, Highway 1 and West Africa Blvd" or "community well" or "village market, east end entrance".

Plus, accuracy is a problem too. GPS is generally good to 30 meters, and can be as good as 10 meters without using Differential GPS. That is a big deal if you are marking the ends of runways, or road intersections, or the edges of cliffs, or the tops of peaks. You might want a GPS unit that can give you an accuracy estimate, or one that integrates over time to improve its own accuracy. Plus it would be nice if it gives you elevation as well as Lat and Long.

If you are just walking down the course of a road, a reading every few hundred meters would be nice. Especially every time you hit a significant turn in the road. A good rule of thumb (maybe just a marginally OK rule of thumb) is to not get out of sight of the last spot you took a reading at. It is like having a trail of breadcrumbs when you take all those data points and try to build a map from them.

Last tidbit: you might want to stop by a Professional Land surveyor's office before you go, to see if he (or she) has any tips for you. They do this sort of thing for a living.

Re:Be careful!!

[Daniel_Staal]

Many African governments are currupt, and would love to do ethnic cleansing.

Most African governments in my experience (check my bio if you want to see if I have any) don't really care about ethnic cleansing.

Taxing, on the other hand, is something every government wants...

Africa is more civilized than most people realize. For good and bad.

Re:Be careful!!

[Anonymous Coward]

Spoken like a true white South African. Yep, you're technically African.

Re:Be careful!!

[machinegunhand]

Yes, indeed you must be careful. Anyone who's ever watched Gilligan's Island knows there's a lost tribe of headhunting canibals out there somewhere, just waiting for some well-meaning city folks to wander into their territory.

Re:Be careful!!

[Anonymous Coward]

Let's be honest with ourselves here, and admit that generally corruption is quite a bit greater in African nations than in, say, the EU or US, and that generally their governments tend to be a little less stable.

That said, yes I get annoyed when people refer to "Africa" like it's one big freaking country...and I'm from the US. I mean, the least you can do is break it into the several very distinct regions, if not individual countries. But no...it's always just "Africa."

Re:Be careful!!

[budgenator]

1.[serious] Diamond companies arn't in the USA, in fact DeBeers is prohibited from doing bussiness in the US except for a new retail store they are test marketing.[/serious]

2. [sarcastic]if the company was powerful enough to do that, they's just do it irregardless if the map showed a village or not; a couple tons of napalm is just clearing uninhabited jungle and scaring away the vermin.[/sarcastic]

3.[serious] canabals are located in burma not africa,[/serious][sarcastic] and they only practise it now-a-days on tasty paranoid white european types like yourself[\sarcastic]

4.[serious] touching base with authority figures, both formal and informal is good advice; ask, get permission, proceed.[/serious]

An interesting site

[Anonymous Coward]

You will find the following site very informative
(including creating maps from scratch) although
most of the info. is related to garmin GPS units.

http://www.elsinga.org/home.html

The real-life tron bikes might help...

[Spy der Mann]

Link

I know it was designed as a joke game, but this way you could draw the maps for the roads between villages just by riding on your bike! :D I find that pretty convenient.

NO!!

[Minstrel Boy]

This is totally false and potentially harmful. GPS receivers do *NOT* come with built-in compasses, at least I don't know of any that have them. GPS tells you exactly four things, to various degrees of accuracy and precision:

latitude, longitude, elevation, time

*Everything* else is interpolated from that info, and if you lose satellites, you lose everything. Even if you stand still, GPS won't tell you where north is; you have to be moving so it can triangulate.

A GPS has some capabilities that overlap with a magnetic compass, and vice versa, but it is extremely risky and potentially hazardous to substitute one for the other.

That being said, I don't know what the OP was planning to do with a compass for mapping villages anyway: a compass doesn't tell you where you are, it only tells you what direction you're facing.

KeS

Re:NO!!

[centauri]

Well, I did tell him to bring a back-up.

Anyway, the compass on my Garmin eTrex C seems to work fine whether or not I have a satellite lock. It can use the GPS data for the compass heading, but only does so when I'm moving above a certain speed.

Re:NO!!

[hilaryduff]

well unless its a mechanical compass glued into the gps, its not going to be much use if the unit fails. obviously the backup/s will come into play. anyone who goes into the bush without survival skills, a map and compass is going to end up in a lot of trouble, and probably as some bleached bones pointing a warning for anyone else trying to play the great white explorer with only modern technology behind them.

Re:NO!!

[Your Pal Dave]

This is totally false and potentially harmful. GPS receivers do *NOT* come with built-in compasses, at least I don't know of any that have them.

I have a several year old Garmin eTrex which has both a barometric altitude sensor and a flux-gate compass built in. It's irritating to have to re-calibrate the compass every time the batteries are changed.

I would imagine that there are probably quite a few more recent models having compasses.

Re:NO!!

[centauri]

You're right. I should have suggested that he bring a backup. What was I thinking?

Re:NO!!

[tomjen]

If you are driving in a desert, it can be nice to know the direction you are traveling so you have less chance of getting lost.

Re:NO!!

[idonthack]

That being said, I don't know what the OP was planning to do with a compass for mapping villages anyway: a compass doesn't tell you where you are, it only tells you what direction you're facing.

Obviously, you were never a boy scout. You can use a compass and a contour map of the area to determine almost exactly where you are. And since every inch of the planet (well, maybe square mile) has had a heightmap or at least an image made of the terrain by satellite, it shouldn't be hard to find one less than 40 years old for the location he will be in. He can use a compass to triangulate from two or more landmarks (mountain tops, clearings, lakes, etc tend not to change within 40 years) and then estimate where he is on the map, and take lat & longe from there.

Of course, if the resolution is high enough, the villages are probably visible from satellite too.
---
If nobody notices, it's not illegal.
Generated by SlashdotRndSig via GreaseMonkey

Re:NO!!

[modecx]

You certianly can tell where you are with a compass and a halfway decent map. Never been a Boy Scout eh?... There's tons of compass tricks, and other ways to determine your location quite precisely with very basic items.

I'd love to share, but I've got to run. I'm sure that it would'nt be too hard to google.

Re:NO!!

[jcouvret]

That being said, I don't know what the OP was planning to do with a compass for mapping villages anyway: a compass doesn't tell you where you are, it only tells you what direction you're facing.

A compass is going to be MUCH more useful to map a village than a GPS will be. Consumer GPS units are only as accurate as they are here in the USA because they use additional ground based signals to improve accuracy. In Africa, the accuracy will be more like 30-40 meters. It will be tough to map out a 500m wide village if your references are that "loose".

Use a compass to take bearings on your surroundings. Trianglate the position of a site by taking two or more bearing on obvious features; hills, trees, etc. How do you think all those maps were made before we had GPS - or even airplanes!

Re:NO!!

[TheWordOfB]

GPS Receivers *DO* come with digital magnetic compasses. Your cheaper Garmin or Magellans won't have them, but their upper-end models will. Typically they are implemented via a Honeywell MEMSIC Digital Hall-Effect Sensor. You can get around 0.1 to 0.01 degree resolution depending on the quality of the ADC you have. Generally, most things previously impossible are extremely simple and inexpensive with new breeds of MEMS in a wheatstone bridge configuration. So.. if you're going to buy a GPS, don't buy an older brand trying to pull one more year out of that old design.. get a newer brand which incorporates newer and cheaper technology.

Re:NO!!

[gnomeza]

That being said, I don't know what the OP was planning to do with a compass for mapping villages anyway: a compass doesn't tell you where you are, it only tells you what direction you're facing.
With a compass and a map that is at least detailed enough to show major relief features, your location can be determined by intersection of backbearings.

Re:NO!!

[Ksevio]

You can always buy a compass for $1.00 at your local odds and ends shop and tape it on to a cheap one

Re:NO!!

[courcoul]

While some high-end GPS receivers, especially those for outdoor use, come with magnetic compass functionality, most will give you a heading compass that will tell you where you are going. It only works when you are in motion but is far more accurate than a magnetic, since it is not offset by magnetic anomalies along the way.

Re:NO!!

[neonsignal]

Some GPS equipment also provides 3D velocity measurements, which are calculated through doppler rather than derived from 3D position. In fact, it can sometimes be more accurate to integrate the velocity than to use raw position.

Re:NO!!

[whopis]

Actually even the cheap Garmins have digital magnetic compasses. I have an eTrek series one (don't remember the model number but I know it was only around $100) and it has a digital magnetic compass.

Re:NO!!

[Anonymous Coward]

Then why does my gps have a compass. It knows north from the moment it is turned on before any satalite locks have been made. You should missinform people simply because you have a cheap model GPS and think that it has all the capabilities of the higher end GPSes.

Re:NO!!

[CharlieG]

Most models are available with flux gate compasses today - for instance, that is one of the 2 differences between the Garmin G60C and g60CS (S is for sensors) - the other is a barometric altimeter

Re:A couple of answers

[winkydink]

But in this case, the G does stand for Global. We're not talking about GSM. So what exactly is your point?

Suspicion of the poster

[billmaly]

I suspect he was asking about GPS hardware working overseas (from the US perspective here) becauce of cell phone issues. Most cell phones used here in the states will not work in foreign countries. I suspect he wanted to insure that the GPS he bought here in the states would not suffer the same problem. Good news is, that the GPS signal received is the same everywhere, so no matter if you buy your unit in Butte, Montana or Dar es Salaam, it will work no matter where you carry it. Provided it has power, but that's a different thread.

Re:Suspicion of the poster

[Locke2005]

Except for the GSM phones for use with T-Mobile and AT&T, which simply require a new smartcard to work in almost any country in the world. Yes, the US, in it's infinite wisdumb, decided to push different standards than every other country in the world, not be familiar with basic economic concepts like "economy of scale". And no, cell phones have absolutely nothing to do with GPS, except that some cell phones now contain GPS receivers.

So...

[Anonymous Coward]

you're not up to an easy task. I'd recommend grabbing a book on basic mapping/surveying at your library, but here's som questions you should answer before you start:

* What will the map be used for? Registering houses? Digging sewers? Mapping roads? Plotting land? 3D landscaping?

* What's the budget? Surveying grade GPS equipment can easily cost you $50.000. A steel measuring tape costs $50 and can get you just as far depending on the job. Maybe you'll be better off with tradidional surveying instruments (total station, prisms etc.).

* Which accuracy do you need? If it's 10 - 30 meters, you can use a normal handheld GPS. If it's 2-10 cm, you can use a differential GPS system, but you'll need a base station.

* Which coordinate system? Is this a local project, or do you need to hook the map up to a global coordinate system, eg. UTM? Do you need to join your measurements with other maps?

* And finally: which maps do you have accessible already? Satellite imaging? Local maps - paper or digital?

Mapping programs could be anything from a spreadsheet and Pythagoras to fullblown ArcInfo or specialty software, eg. Trimble Geomatics Office. Open source GIS solutions also exist. See http://www.opengeospatial.org/

Erik

Undeveloped Countries?

[Anonymous Coward]

I think the parent poster Floodimus meant 'developing' countries instead of using the term undeveloped or underdeveloped countries, which implies an inferior society with archaic and anachronistic practices. 'Developing' country a better term to use and doesn't sound pretentious.

Best mapping and spatial software available

[Hungus]

I would go with PostGIS and Grass on your Mac if GIS data is available for her region ( and it is). Then you have a nice database system to drop all your GPS data into for mapping and a boatload of other uses.

GRASS GIS (Geographic Resources Analysis Support System) is an open source, Free Software Geographical Information System (GIS) with raster, topological vector, image processing, and graphics production functionality that operates on various platforms through a graphical user interface and shell in X-Windows. It is released under GNU General Public License ( GPL ).

Re:Best mapping and spatial software available

[Anonymous Coward]

You've obviously never used GRASS and any other GIS software. GRASS is definitely NOT the best.

Re:Best mapping and spatial software available

[Anonymous Coward]

I'm a professional cartographer with access to pretty much all the major GIS packages at work. I use GRASS every day. It rocks!

Caveat. It seems to be for and by power users, and it helps if you have a background in UNIX as it is very unixy.

You don't have a girlfriend

[Anonymous Coward]

C'mon now, this is slashdot, we all know you don't have a girlfriend, so why not let us in on the real reason you're mapping africa?

MOD PARENT UP

[Anonymous Coward]

One of the most insightful responses I've read to this article.

HOW to do this

[zandermander]

I'm sure many others will cover equipment, power charging and such - I'll cover how you should do this. Well, since I taught in a developing country for a few years, this is my suggestion of how...

Developing countries generally have a huge surplus of labor - it's one of their biggest resources. They also, like a lot of the world, tend to have lots of kids who are eager to learn new stuff.

What you need to do is take several GPS receivers with you and hook up with a local teacher who can integrate GPS ideas and geography in with their lessons. The teacher could even make it a special project working with trustable students to map their own village(s).

The key here is to push as much onto the students as possible so they do the work and they learn. You'll help the teacher, help the students and help make more than just maps.

Re:HOW to do this

[apraetor]

Oooh! Can we design a lesson around sewing sneakers?

Re:HOW to do this

[sheldon]

Naw. The kids get paid for sewing sneakers.

G in GSM != Global

[winkydink]

Do your homework. GSM stands for:

Groupe Speciale Mobile

Maybe my French is rustier than I thought, but I believe that traslates (roughly) as Special Mobile Group.

Re:G in GSM != Global

[Ronald Dumsfeld]

Do your homework. GSM stands for:

Groupe Speciale Mobile

Shhh! That's just what we want the French to think. Nobody else has to believe it.

Re:G in GSM != Global

[uberdave]

The GSM group ("Groupe Spécial Mobile" (French) 1, 2, 3 and 4) was founded in 1982. The name of the system comes from the name of this group, though later the decision was made to keep the initials but to change what they stood for.

I guess both viewpoints are right.

Re:G in GSM != Global

[Espectr0]

Do your homework. GSM stands for:

Groupe Speciale Mobile


From wikipedia:

Global System for Mobile Communications

source

Re:G in GSM != Global

[winkydink]

Notice how it glosses over the GSM patent-holders agreeing to the change. They didn't. The change was a feat of American marketeering. Just because Wikipedia says so doesn't mean it is so.

How do I know? I work for a company that subcontracts in the GSM area for one of the patent-holder companies.

Re:G in GSM != Global

[spaceyhackerlady]

Just because it's in Wikipedia doesn't make it true. Just because it's on the Internet doesn't make it true.

GSM really did stand for Groupe Spéciale Mobile at first. But some people from a certain country with an aversion to languages and the rest of the world generally decided it needed an English acronym.

f I was going to Africa, by the way, I'd take at least three GPSs, the simplest most generally robust model I could find. If the local authorities were mor pro-Russia I'd scrounge some GLONASS gear too. I'd take a gross of AAs or whatever they took. I'd ditch the laptop in favour of printed notes (no batteries, you see...) and whatever maps I could lay my hands on.

...laura

He's lying...

[Anonymous Coward]

He must be lying. He's not going to Africa. He probably wants this information for some pro-Microsoft, anti-Linux, pro-spammer escapade. I mean, he practically gave it away by starting with "My girlfriend...". C'mon, let's be honest, a Slashdotter with a girlfriend?

Workable Solution

[Mik3D]

Your best bet for a workable cross platform solution that can handle a variety of data types is probably qgis.

For simplicity sake you might look into prebuilt basemaps like these I am pretty sure qgis supports the bsb format.

QGis will allow you to import GPX files from a consumer GPS unit.

GPS is half of the problem. GIS is the other

[Greg151]

You need to look at some GIS ( geographic information systems) http://www.gis.com/whatisgis/index.html/ software to construct maps, measure distances, and do analysis of the data collected. There are some free versions, as well as one or two good commercial platforms. If you are doing this for charitable or scientific reasons, the companies will generally help you with free licenses.

apocryphal software bug story

[mkcmkc]

Dunno if it's true, but I heard a story about an early bug with a GPS-based avionics system in a military jet. They discovered that (possibly during simulation?) when the jet cross the equator, it would flip over, due to some sign bug.

(It's been a while, so I could be remembering the details wrong.)

Mike

Re:apocryphal software bug story

[ben_kelley]

I heard this story before in relation to a software QA program: Introduce deliberate bugs and see if they get detected.

The moral to the story is to make sure that you go back and check that the bugs were actually resolved. Supposedly the plane-flip-over-when-crossing-equator bug was deliberately introduced ("They're sure to pick this one up!") but went through undetected.

I supposed this story was an UL, but some preliminary searches can't seem to turn it up.

Re:apocryphal software bug story

[Anonymous Coward]

It's the Israeli military jets. When testing over the Dead Sea, the navigational systems would suddenly crash. That makes landing very difficult. Ground tests couldn't solve the problem.

You've probably guessed it by now. The Dead Sea is below sea level, so every time the plane dipped below 0 altitude, it would have a divide by zero error.

Re:apocryphal software bug story

[Moofie]

I'd take that with an incredibly huge grain of salt. A GPS unit doesn't know if it's upside down or rightside up.

Re:apocryphal software bug story

[Blastercorps]

I have heard a semi-confirmed story along those lines. It goes that on a group of fighter jets sold to Isreal by the US the navigation system would crash while doing low altitude maneuvers. It was eventually discovered that these jets were ove the dead sea which is actually below sea level. When the jets went below sea level the program puked. The initial designers didn't think a plane could go below sea level without crashing so they never planned for it.

Watch out for Customs!

[Belsical]

Honestly, you'll be lucky if you get the thing past customs without it being 'confiscated.' They take what they want. This happened to my friend who went to Kenya to help set up a network for his missionary friends. They just up and took a router and other bits of hardware that looked interesting to them and told him to move along. Luckily, he only had one CD of software that he kept in his pocket. He knew this was a possibility, but didn't think it really happens. It happens.

If you're going to bring a GPS device over there, get a compact one that will fit in your pocket.

Your girlfriend lives on another continent

[Anonymous Coward]

Hello. Time to get a new girlfriend.

Re:GPS hardware reviews @ http://gpsinformation.ne

[centauri]

How did you find this out? Did you ask slashdot? That's clearly the only reliable way to get good information about GPS.

This is interesting due to the accuracy of GPS

[Anonymous Coward]

Many nautical charts in use today contain information how to correct measurements of coordinates on them since the originals predate GPS and even though they have been updated they are still incorrect compared to positions given by a GPS receiver (the reason why the coordinate system isn't corrected is that all coordinates must be the same as in other references, i.e. if the coordinates of a lighthouse are read from a table or measured from a chart they must be the same - even though they may be different from what a GPS receiver would show on the spot, which would be more accurate). So if this is unmapped terrain the resulting map can be more accurate than many modern nautical charts.

Past experience

[Anonymous Coward]

I worked as a draftsman (among other duties) for a mining company in Burkina Faso in the mid nineties. We did a combination of old fashioned mapping where the geologists would draw out the key features they wanted me to work with while at the same time using a GPS to get the exact co-ordinates of the features. I'd digitise their drawings and then move the various features around within AutoCAD so that they were positioned according to the GPS coordinates.

Doing a combination hand drawing and GPS seemed to provide a good mix between the positional accuracy of GPS and the ability to hand draw key features like the shape of water holes, rock outcrops, and the like. If you're mapping villages you'll want to be able to map trails, well locations, buildings, etc. Depending on the scale of your work you may want to hand draw some of the features.

Something to keep in mind, even if you are very careful with your GPS and laptop you can expect them to have a much shorter useful life while in West Africa than you might be used to in cooler and less dusty climates. 6 months was an average for our laptops and we were careful with them. Also be aware that if you need to replace electronics while there it will be much more expensive than you are used to. If you can, take two GPSs.

Have fun, don't leave electronics (or anything plastic) on your dashboard - it will melt, and good luck with spelling the village names! It sounds like a fun project.

Re:Past experience

[HermanAB]

"Have fun, don't leave electronics (or anything plastic) on your dashboard - it will melt, and good luck with spelling the village names! It sounds like a fun project."

No, it won't melt. It will get stolen looooong before it can melt.

General rule of thumb: Anything that won't fit in your backpack, will get stolen and if you let your backpack out of sight for 0.000001 seconds, then it will get stolen together with everything in it.

Note that for protection, it is a good idea to carry a hunting knife, but since some places object to knives, consider carrying a small axe instead - there are no laws against axes and it will ensure that you'll be a very popular guy whenever you set up camp and need a fire...

MapInfo GIS works fine

[WillAffleckUW]

and I used to program some scripts for Nextel that used that on Macs.

However, I am NOT certain that the version we used, which had commercial GIS plug-ins for error correction, can be exported outside of NATO.

Remember, they just applied penalties to MSFT for breaking the restrictions, and they can afford tons of lobbyists and lawyers to keep them from going to jail - a small-time developer is more likely to end up being shipped off to Gitmo no questions asked ...

Works but not as well

[psychofox]

Sure a GPS works anywhere in the world, but only the Americas and Europe have the corrective signals that give accuracy in the sub 10 metre range. WAAS and EGNOS respectively.

See
http://en.wikipedia.org/wiki/WAAS
and
http://en.wikipedia.org/wiki/EGNOS

Toughbook

[Sawbones]

You say you use both mac's and PCs but if you haven't decided on what equipment to use in the fields I highly recommend the Panasonic Toughbook. Some are "tougher" than others, water proof vs water resistant for example, but all of them can take a severe beating and keep working. Legacy ports too so it's easy to interface with old Garmin gear.

I have a 72 (replaced by the 73 in recent years) and it's been everywhere with me. They're a little heavy, but you can drop them from a meter onto concrete surfaces and have them work so that's worth the extra weight. There are some solar chargers available too, for times when you're far away from the grid.

If you're strapped for cash and don't mind a slightly slower machine you can usually find good deals on ebay. The P3-800 range - my machine - can be had for about $500, and the lower end PS-300's come as cheap as $200.

Surveyors - do it best.

[Anonymous Coward]

To produce useful maps you need a decent package of surveying software. By using differential GPS and an approriate set of post processing software you can get down to millimeter accuracy reasonably easily.

I think the suggestion of using satellite photography has merit. But it depends as to what detail you wes to resolve to. Commercially available sattelite photography can be expensive and only resolve to a couople of meters. From that you won't be able to pick up much of the infrastructure information that would actually be useful.

Once you have collected all of this information you will want to geocode it as lines, polygons, etc which is usually done through software packages put out by esri or mapinfo. These are expensive - not sure if there is an open source equivelent out there.

Follow this process.
1. Determine purpose of mapping
2. Determine equipment required to meet that purpose
3. Profit ! Oh wait get a warm glow from provideing a useful service to an underdeveloped community !

Satellite Imagery, GPS and power.

[refactored]

Go there with the highest resolution satellite image prints you can lay your sticky hands on.

Use a GPS, make sure you can feed it off 12V car and whatever the local power is.

Make sure the technology level you are bringing in is appropriate to the technology the people can afford. Sure you may be able to tell them exactly where Village A is in lat/lon. They know which path to take / which taxi minibus to take anyway. Have you really helped them?

Often the problems are a _lot_ more basic. Getting clean water to the house. Low tech user servicable pumps are often better than latest greatest sealed units. Desposing of waste safely, preferably in a field fertilizing manner. High yielding and disease resistant crops that require no agrichem would be handy. Vitamin supplements for the kids.

Do the air ticket open market test. Go to the local largish town. Go to the market place. Often they are absolutely fascinating places. Mentally spend the price of your air ticket, at that market, on things the local people you care about need for a healthier, safer better fed life.

Find out what it takes to find,prescribe,buy a bog standard antibiotic effective against common problems in the area. eg. Amoxylin.

Frightening, wasn't that?

Watch the mercede-benz crowd arrive at the airport. Where do they go? What are they doing? Why are they so rich in a land that is so poor? (Hint: Don't watch too closely, it is hazardous to your health.)

Mac Software

[vangilder]

I've had a very good experience with MacGPS Pro from James Associates. It's reasonably priced ($40) and you can even find free maps and such. I used it in combination with a Garmin eTrex on a recent trip to the Okavango Delta (Botswana) and it worked just fine. No, I do not work for either company.

Only If...

[Herkum01]

the area has been labeled to be harboring terrorists. Then GPS will work, but only for bunker busting bombs or anything else that can be used to kill someone from the air...

YES!

[Rolan]

Actually, there are GPS recievers that DO come with compasses (magnetic ones), though they are typically on the higher end ones.

Solar Power

[PortWineBoy]

I saw this on Engadget just today.

Your GPS would need a work visa

[pg110404]

does GPS equipment from the US work over there?

I'm sure it functions just fine over there, but I wouldn't count on it settling down and getting a job there without applying for a work visa first.

Re:Your GPS would need a work visa

[HermanAB]

Well, actually a GPS will develop legs and run away soon after arrival. (To Westeners, that means it will get stolen immediately after arrival in Africa). Also, a GPS with a flat battery is just a paper weight, but a paper map with a hole in it, is still a map. I would get the best maps and satellite photos possible, then use a compass to take sightings of mountain peaks and triangulate.

Re:Your GPS would need a work visa

[pg110404]

I would get the best maps and satellite photos possible, then use a compass to take sightings of mountain peaks and triangulate.

That sounds an awful lot like how they did it before GPS came around. You'd be amazed how accurate a map you can create with an accurate wrist watch, the sun, a compass, a good stack of writing paper and a good amount of effort.... But I suppose it's the effort part that puts off a lot of people.

Re:Your GPS would need a work visa

[HermanAB]

Anyway, in Africa, distance is measured in days, not kilometers. Victorian age maps were frequently marked with the word MAMBA: Miles And Miles of Bloody Africa.

Rhino decent GPS

[kyndig]

The Rhino 120 GPS is what I've used for the past 6 months in and around the middle east. It is lightweight, and interacts with the PC to support uploading of Rastermaps. Zoom capabilities allow for viewing at global scale, down to a 10 digit grid.

The Rhino is fully customisable, and comes with a few games for those days that you just don't feel like doing anything =). The map upload support is the best feature of this little gadget IMHO.

Waypoints, paths taken, current location, remote location of others using the Rhino, walkie talkie, basic security measures, multiple grid system formats (lat/long,GDS,MGRS,Asian/European,etc..) .

It eats up batteries, so make sure to have some rechargables around.

I use 3 types of GPS systems when out and about. A basic military PLGR, the latest technology in GPS that costs more than I make in 5 years, and this handy little Rhino. When I'm asked for my current location, the Rhino is the first thing I grab.

Some countries a depleted uranium detecter will do

[Anonymous Coward]

Some countries can be mapped using a "depleted" uranium detecter. It just depends upon how recently it has been Americanized.

Be careful of paranoid thugs in uniform

[aggressivepedestrian]

Having worked and travelled in various parts of Africa, I urge you to be careful regarding mapping. You didn't mention where you are going, and perhaps it will all work out, but many police and military units in Africa will prevent you from taking pictures of "sensitive" subjects like bridges or government buildings. If they don't want you taking pictures, one can only imagine how they would feel about recording GPS data.

Be ULTRA careful

[FitGeek]

I travel in and out of Africa about once a month on business, hitting about 15 countries on average each year. I can tell you from experience that it is VERY dangerous to be seen using a GPS near Military installations, railroads, shipping, and anything the locals consider of strategic value. This generally means about everything. You should be extremely circumspect when using the GPS. You may have it confiscated, or you may end up in a cell somewhere with arabic graffiti on the walls. Not good. Your best bet is to make sure you contact your local embassy in the country, and ask their communications personnel about local sensitivities to GPS. You could always ask the Regional Security Officer (RSO) also, but be forewarned that they often err on the side of safety, have a poor understanding of much tech, and could very well say not without a moment's hesitatin to avoid having to retrieve you from your cell when you are snagged. Best bet; use it for quick position fixes, then put it away. It is also not safe to display an item that costs more than most locals make in a month of hard labor. Good luck!

Re:Be ULTRA careful

[Anonymous Coward]

Given the risks involved, why bother. Especially considering that all the hard work you do can be duplicated with ease by someone sitting in an armchair with properly registered orthophotos. I.E. - whatever work you do in this arena will likely have a very short shelf life. Don't bother.

Re:Be ULTRA careful

[Port-0]

It's true, be discrete. Though, most likely the worst case is probably they take the GPS away, and haul you down to the police station for a while, until you cough up a bit of cash. Being from North America or Europe makes you an instant target for trying to get a quick bribe. If you are out in the middle of nowhere, no one's going to care that you have a GPS, most people won't have a clue what it is. Just be careful about having anything electronic visible around the authorities. Get a small GPS unit, and keep it in your pocket.

I did a bunch of mapping in central Mali about 10 years ago. I was helping a guy map wells in abandoned towns (they were abandoned because of the Twarag war which had ended a few years earlier. He was doing a survey to see which villages had a useful water supply, and which needed work) Anyhow. It's not likely you would get in overly serious trouble for having a GPS. Bring two in case one gets confiscated or broke. A low cost Garmin GPS works just fine (they are rugged enough), I was getting acuracy to + or - 19meters when I was there. It should be much more accurate now.

With a paper map bought at your local book store, a ruler and some simple math, you can put together a quick map. Some of the other mapping software mentioned in other posts works better for custom projections, but can be much more involved and time consuming. Double AA batteries are plentiful in Africa, so powering a GPS is no problem, though when you buy them, try them while you are there and make sure they work. If you are spending serious time on a laptop out in the bush, the best bet is to have an inverter to plug into a car, or a solar panel if you want to be fancy, and have extra money to spend.

The sand in the dryer areas of West Africa can be hard on equipment. I was in a sandstorm once, my video camera was never quite the same after that. The humidity in other parts of West Africa creates it's own problems, but nothing that can't be worked around. I had and still have a Garmin GPS 45, which survived traveling a large part of the globe unscathed, and continues to work 10 years after I bought it.

Keep it as simple as possible, keep freqent backups of data, and don't take anything with you that you aren't willing to part with.

Have fun

Re:Be ULTRA careful

[JakartaDean]

I had some work in Sudan last year, and it is pretty much illegal to take photographs. You first need to get a permit from an office which never opens, and then you are banned from photographing a long list of buildings and structures, including pretty much everything owned by the government. Since the economy sucks, pretty much everything in Khartourm is owned by the government, so nothing to snap. I took my camera up into my client's office building one day anyway, took a few snaps out the windows, and got a thirty minute interrogation from Security for my transgression. But, compared to Sudan, Ghana is likely paradise.

Re:Be ULTRA careful

[anticypher]

This point can't be hammered home hard enough. Know the political climate before you set foot in the country with a sack full of espionage equipment. If I can be forced by a Massachusetts state trooper to reformat my digital camera memory or face arrest on terrorism charges because I had a bridge in the background of a photo, expect it to be much worse in places with civil wars or low grade religious conflicts.

Make sure the organisation you are working for supports your mapping effort 100%. If this is just a personal whim, leave the high tech goodies at home, and think about doing a paper and pencil project. When (not if) you get arrested for waving a GPS wildly around at every crossroads and bridge, there better be a powerful politically connected group ready to put pressure on the local police to release you. If you don't have this, expect to spend a long time in jail until the appropriate fines/bribes can be paid.

You have to worry about the military and police, of course, but also private security guards working for the big money projects. Oil exploration, mining, civil construction projects all have their own cartography services, and there are certainly accurate and detailed maps of every part of western africa, but those maps are closely guarded secrets. In Nigeria, security guards for oil companies *are* the police in many cases.

Be discreet no matter what you do, and don't pull out espionage equipment until you have scoped out the area and know exactly what you will be measuring. If there is a military base just behind a hill, you don't want to be caught targeting its perimiter. Leave the kit at home until you are ready to go out and make measurements. Hire locals who know the landscape to help you avoid trouble when you venture beyond your base town.

the AC

Re:NO!! (ok, just Nope)

[Minstrel Boy]

Looks from the Garmin feature comparison like they're starting to incorporate them in some units - per the Garmin site the Summit, Legend C, and Etrex C are the handhelds that have an electronic compass. None of my GPS units have ever had them. Good to know, thanks!

I wonder how they resolve the local isogonal flux variations (which the compass knows of and the GPS has no clue about).

I recognize that this borders on trivia, and it may not matter much for ditzing around the local geocache, but if you're headed out on a big undifferentiated body of land/water it can get pretty significant pretty quickly. Thanks again for the update on the Garmin units.

KeS

More accurate readings

[denissmith]

GPS can and does yield more accurate readings than the 20 meters in some situations. The accuracy problem is caused by the US military screwing with the clocks. Which is one reason why some countries don't want the USG to own DNS, but that debate does not belong here, it belongs somewhere else on /., whereas you just want super accurate GPS readings, so.... You need one known earth reference ( Here in the US there are lots of known survey markers, but where you are going they may be harder to find). Next you need two GPS receivers and two 2-way radios. One GPS receiver will occupy the known geo-reference point for the entire data collection period. The other receiver moves through the survey area and data is recorded at exactly the same time on the two receivers, one at a known point one at the survey point. You can now mathematically eliminate your error ( and get your survey accuracy down to around 1 cm if you need to) by using the known geo reference point as a filter. There are very expensive software packages that can automate this for you. The best place to look for help would be in university geography departments that have photogrammetry course work. You could also contact photogrammetric mapping companies directly, but they may not be interested in pro bono assistance.

Re:More accurate readings

[TopSpin]

The accuracy problem is caused by the US military screwing with the clocks.

Selective Availability was turned off half a decade ago. Whatever clock drift exists is just normal, unavoidable error inherent in trying to keep multiple spacecraft clocks synchronized.

Most of the inaccuracy of GPS is caused by normal clock drift (both in your GPS device and the satellites,) and signal problems caused by the ionosphere or multipath. A good GPS receiver can mitigate clock error anywhere on the planet if enough satellites are visible simultaneously. Multipath signals and ionosphere problems are just a fact of life with radio signals. Africa doesn't have WAAS so these errors can't be mitigated.

...and no, the "US military" isn't distorting the ionosphere over Africa to make GPS less accurate.

Re:More accurate readings

[Anonymous Coward]

"The accuracy problem is caused by the US military screwing with the clocks."

That is called Selective Availability, and was removed about 5 years ago. See: REMOVAL OF GPS SELECTIVE AVAILABILITY

Re:More accurate readings

[birge]

I can't argue with anything you said, except for your assertion that the signal isn't degraded over other parts of the world. You don't know that, and it's perfectly possible the US is degrading the signal over Africa. There would be good reason for them to do so, especially over northern Africa. Given that they could, why are you so sure they don't?

Re:More accurate readings

[ckaminski]

From: http://www.tech-faq.com/gps.shtml

GPS satellites orbit the earth at an altitude of approximately 20,200Km.

Each GPS satellite has an orbital period of 11 hours and 58 minutes. This means that each GPS satellite orbits the Earth twice each day.

These twenty-four satellites orbit in six orbital planes, or paths. This means that four GPS satellites operate in each orbital plane.

Each of these six orbital planes is spaced sixty degrees apart. All of these orbital planes are inclined fifty-five degrees from the Equator.

Result:

You cannot affect one country with GPS degradation without also affecting dozens of other countries under the satellite's horizon. It is NOT possible to single out a country for signal degradation like you propose. Either the entire system gets degraded (when selective availability is turned on), or they all get the same resolution.

Note this doesn't take into account ground-based radio reference stations, DiffGPS, WAAS, etc. The GP was correct.

Re:More accurate readings

[jools360]

In Africa you should get around 1.5-2m accuracy with a modern receiver which can also receive EGNOS DGPS corrections. Almost any modern GPS worth it's salt can receive these corrections, they are free, and transmitted on the same frequency as GPS, so you don't need any secondary antennae. The US have now recently developed ways of degrading the signal in different parts of the world, I think there are a number of subtle ways of doing this, but not necessarily by skewing of the GPS clock. Having said that, none of our customers are reporting any problems at the moment in Africa.

Re:More accurate readings

[birge]

I appreciate your thoughtful and factual response. However, I didn't say they would screw up the signal in one country. I said Africa. Of the top of my head I don't know the "field of view" of a single satellite, but I'd guess it's a significant majority of the hemisphere it's over. However, it would only take screwing up the one or two satellites that are over southern Africa at any given time to mess up the signal for Africa but not much affect Europe, since you need at least 4 to get a good fix. Maybe they'd just say the heck with it and always have some sort of SA turned on for any satellite not usable from America. I don't know, but I'd be surprised if the military COULDN'T do that, and it seems like they would if they could since they are under no obligation to provide anybody but America with a good unencrypted signal (by Clinton's executive order).

GPS will work, WAAS will not

[Paranalense]

I think nobody has noticed that a WAAS enabled GPS will not achieve the precision given by WAAS, but only the standard GPS precision (somewhere between 20 - 5 mts.). In other words, a WAAS enabled GPS WILL work, but it will not use its WAAS feature at all. If the guy is going to buy a new GPS, don't make him waste extra on a feature he won't use.

Re:GPS will work, WAAS will not

[Anonymous Coward]

The EU version of WAAS (EGNOS) is 100% Compatible with WAAS GPS Recievers, and will work just fine all over Europe and even Russia.

US Call it WAAS
EU Call it EGNOS
JP Call it MSAS

But it's all the same thing

Re:GPS is half of the problem. GIS is the other

[WillAffleckUW]

the other thing is the error correction routines for GPS coordinates are usually NOT exportable outside of NATO, even the commercial satellite feeds.

Satellites?

[purduephotog]

Contact the National GeoSpatial-Imaging Agency and see what coverage LandSats have over there.

Download the ortho-rectified maps.

Follow the roads you can see (30 meter resolution)

GPS? Disable WAAS and get an external antenna

[LetsGoVandy]

If you do carry your USA-centric GPS across the Atlantic to Africa, save yourself some battery power by disabling WAAS - the Wide-Area Augmentation System. The US has augmented the GPS sattelites with two WAAS satellites, positioned in geostationary orbit above the East and West Coasts. The signals from these "fixed" positions provide a differential method for enhancing accuracy. However, from Africa, trying to use WAAS will waste power and possibly inflate the error in your position.....Also, if your unit permits, an external antenna will do wonders. Carry it on a stick, mount it to your Land Rover, etc., and hide the digital equipment from prying eyes, dust, and weather.

Re:GPS? Disable WAAS and get an external antenna

[rikkards]

Way back (1990-91) my dad was testing out a Trimble GPS (big green thing with dipswitches) for the Canadian Military and we took one on a trip from Ottawa to L.A. It had the little egg shaped antenna. Everyonce in a while at a truck stop someone would ask what it was. We would say it was for a radar detector or cell phone.

This was early enough that more often than not we got "Not enough satellites"

ExpertGPS

[Anonymous Coward]

ExpertGPS allows you to import your own maps -- even hand drawn ones -- and 'coordinate' them with your GPS...

Precision of GPS outside of NATO

[WillAffleckUW]

Thanks to the precision and accuracy of modern electronic hardware, this calculation can be accurate to within 20 meters or less.

However, while GPS is accurate to less than a meter with error-correcting commercial or military signals [the military pulled out part of the bands, those big holes you see on the spectrum map], the commercial software/hardware allowed for export outside of NATO does NOT have this accuracy.

It's usually only accurate to about 150-200 meters.

Re:Precision of GPS outside of NATO

[slew]

> Thanks to the precision and accuracy of modern electronic hardware, this calculation can be accurate to within 20 meters or less.

However, while GPS is accurate to less than a meter with error-correcting commercial or military signals [the military pulled out part of the bands, those big holes you see on the spectrum map], the commercial software/hardware allowed for export outside of NATO does NOT have this accuracy.

It's usually only accurate to about 150-200 meters.

Not sure this is entirely accurate...

Certain GPS equipment is classified as a munition (e.g., one that is designed to produce location data at altitudes > 60,000ft and velocity > 1000 knots), but most commercial ones don't have the required capabilities and are usually exportable.

Also since selective availablility has been turned off (worldwide since 1998), the C/A code(the commercial one, not the encrypted military PP code) will generally give better than 40meter accuracy (average 15meters), depending of course on how cheap you are with your equipment...

Garmin GPS 60 & Geocaching

[metoc]

The GARMIN GPS 60 is a basic handheld GPS, is very water resistant and dust proof. Two AA batteries (which you can get anywhere) will get you 12 hours continuous operation. It is also fairly inexpensive so take two.

Garmin provides their MapSource mapping software which will allow you to archive everything the GPS 60 can record, including waypoints and tracks. The Geocaching crowd also has plenty of software, I prefer EasyGPS.

Concentrate on collecting data in the field, and make plenty of copies. Worry about post processing later.

Lastly. Learn how to use it before you go!

danger will robinson

[Anonymous Coward]

your girlfriend lives in a remote unmapped country in west africa...
get yourself tested for HIV, like yesterday.
no joke.

Yes! But not all.

[CRepetski]

It is true that some handheld GPS units do not come with a built-in compass. In this case, you will need to have a satellite lock AND be moving in order to find north. (My Magellan Sportrak Pro falls under this category)

HOWEVER, many handheld GPS units, especially slightly higher end ones DO come with built in compasses, and can tell you which way is north even when you're in the basement of a building with absolutely no satellite reception and you're not moving. (My Brunton MNS falls under this category)

Bottom line, you should know what you're buying and what features it has before you get it.

On a somewhat related note, having a built-in compass can be extremely useful, as it will tell you how far away and in what direction a mark is even when you're not moving - it will tell you relative to the orientation of the GPS. Many units without a built in compass only tell you in what direction a mark is relative to direction of travel - so this can be very confusing if you're standing still or haven't oriented the unit in the direction of travel. Hope this made at least an inkling of sense.

Re:Yes! But not all.

[olivercromwell]

OOPs. Last post was meant to be nested under MinstrelBoy, and for some reason I am not able to change it. Sorry.

Re:Yes! But not all.

[Minstrel Boy]

No, I wasn't a Boy Scout. I mugged Boy Scouts. ;)

My compass analogy was to the GPS - all GPS can tell you directly is the lat/long/elevation/time, but a good receiver can extrapolate a lot more useful information from that. All a compass can really tell you is what direction you're facing (and even that is relative to local magnetic fields, as noted by many). With the aid of other tools, yes, you can also extrapolate a good deal of other info. My navigational experience is largely offcoast marine, so the topography is pretty featureless. ;)

KeS

Riiiiiight....

[RapmasterT]

My girlfriend lives and works in West Africa and on my next visit she has asked me to help her do some mapping of uncharted villages

My girlfriend lives in Canada, you haven't met her...

Not that this post will ever be seen but I tried

[deangelo]

Most of these posts are not going to help the submitter much at all, mostly because nobody here seems to know a damn thing about GIS. First things first, what sort of mapping are you trying to do, what information do you want to gather? Hydrology? Land use? Topology? Classification? Next most of the consumer grade stuff is crap if you want any kind of accuracy, if you want really good data, you'll need to get a base station set up and look into dgps, that means you need a better sort of GPS unit such as something from Trimble. Next, GPS compasses, be they electronic, interpolated, or what not are crap. BRING a GOOD compass. You'll probably also want a separate barometric altimeter, and a clinometer, if you don't know how to use and calibrate this equipment, then I must agree with the earlier post that amateur cartography might not be for you. As for software, again really depends on what you are trying to do? orthorectify photos? network analysis? etc...
In short, good luck.

BTW, I have SOME qualifications, a GIS minor, and my Msc thesis(in progress) is about robotic terrain mapping.

GPS Recommendation

[Anonymous Coward]

GPS works more or less world wide (less well at the poles and in dense forrests. How else could we bomb these places ;-)?

Make sure the GPS comes with a universal travel charger that can take 100-240 V. Get a car kit as well. It helps if you can mount it on a dash board instead of having it fly around the car.
Don't count on the batteries of the device lasting more then a couple hours. As far as features go: Many of them help the unit to be faster. If you take stationary measurements, the cheapest one will work just fine.

There are two types that will work for you:

Handheld units: rugged and can work without laptop. The very cheap versions do not come with a PC connection. You will likely need a special cable to connect yours to the PC. I highly recommend these units. If your PC dies, you can still collect the data. Most units will store many hundred 'waypoints', and a pen/paper will do the rest.

USB "turtles": I got one like that for wardriving. About the size of a matchbox. But only works with PC (no display). It is magnetic to attach to the outside of the car.

Don't spend a lot of money on antennas. They will not improve accuracy much. A big antenna is only important if your reception in marginal (dense forest).

Now there are a few features which will not work in Afrika:

WAAS uses terrestial signals to improve the accuracy. But no sweat, it will be good enough without it. WAAS is more important for car navigation to figure out if you are on the highway, or the small road next to the highway.

Build in maps are probably not available for your area (why else would you try to do this ;-) ).

Use GRINGO not WAAS

[monopole]

While GPS works everywhere, the Wide Area Augmentation System (WAAS) is only useful for the Continental US. WAAS units will work elsewere but they will only have the resolution of standard GPS. If you need better than standard C/A code accuracy use Carrier Differential (CDGPS) mapping using two Garmin recievers and a copy of GRINGO (http://www.nottingham.ac.uk/iessg/gringo/).

The Garmin Rhino units w/ integrated FRS Walkie Talkie units are vaery rugged and may be handy for survey. Additionally, to quote the Operation Iraqi Freedom
PEO Soldier Lessons Learned report:

Commercial GPS: As is widely known, many soldiers purchase their own GPS systems rather than use the PLGR. The Rhino was provided to the 82d as part of the rapid fielding initiative. Overall, soldiers were very appreciative of this addition to their MTOE. The Rhino was a vast improvement over the PLGR because of the weight, volume, power consumption and performance - the Rhino consistently acquired satellites faster than the PLGR. However, the soldiers stated they did not use the communications capabilities of the Rhino, at least not extensively, because it was not secure and consumed batteries too quickly in this mode.

If it survives the front lines in Iraq, West Africa should be a cake walk.

Re:Use GRINGO not WAAS

[BackInIraq]

The Rino is a great device, but I'd go with a standalone Garmin GPS over it, given the choice now. I've yet to find a way to turn the radio off by default at power-up, and it is annoying having to shut it off every time...and yes, it does burn through batteries MUCH faster with it on.

And a standard GPS will probably be more than accurate enough...mine generally gives a 3D accuracy in the 5 meter range (and I've checked it against a PLGR that has been on averaging mode), without WAAS, which for mapping villages should be more than sufficient. Sattelite acquisition, from powerup, even after dramatic geographic relocation, is still generally in the 2-3 minute range...or less.

And yes, the Rino, along with most outdoor-oriented Garmin GPSs, is more than tough enough for the task.

Re:Use GRINGO not WAAS

[Curmudgeonlyoldbloke]

Not that it's relevant for West Africa, but WAAS aware GPSes does work elsewhere - with EGNOS in Europe (or at least in the UK and, I think, Finland).

Of course, if you're mapping villages (like the poster) then 3m accuracy is probably way more than you need.

Re:Use GRINGO not WAAS

[CharlieG]

Biggest problem with both WAAS and GRINGO in Africa is that there is not likely to be a local CORS station to get a reference from - remember, the closer you are to a CORS (continuiously operating reference station) the better your accuracy - and the CORS data is what is used to generate the WAAS signal, AND used for the post processing in GRINGO

It doesn't matter

[Anonymous Coward]

A compass only helps find where you are if you have a map. If he had a map, he wouldn't need to make one would he.

Re:It doesn't matter

[hilaryduff]

well there are maps, and maps! i think he is planning to map the locations of villages, which probably arent on the maps.

Learn how to use a map and compass.

[RJSIII]

A compass, if you know how to actually use one with a map, can tell you a great deal about not only what direction you're headed, but where you are and, more importantly, it can do something that GPS Just Plain Cannot Do, namely, it can tell you where that unknown landmark is, which in Western Africa is an incredibly useful skill. The last thing in the world a foreigner should do is wander into an uncharted village. Best to get an intersection on it from range, record the position, and move on. Now, this doesn't mean that you shouldn't use GPS. In fact, GPS can be used in conjunction with the intersection technique in order to give you your 'known points'. But don't rely on a single piece of equipment to find your way around some petty warlord's backyard.

Why standalone?

[scdeimos]

There's plenty of GPS solutions out there for PDA's and notebooks using CF cards, PCMCIA cards or Bluetooth.

Why don't you find something you can stick in your notebook, then you only need to worry about charging your notebook? Most notebooks these days come with an auto-switching power supply and you can even use cigarette-lighter chargers in the car. Plus, you can do all of your waypoints and mapping on the notebook in realtime and not have to muck about with pencil and paper or waypoint memories in a handheld GPS unit.

Solar-powered recharging gear

[geovangelist]

Some suggestions for keeping your gear charged up... Portable solar panels: http://www.moderntradingpost.com/powerdock/ and Voltaic backpack with solar panels: recharge small devices with solar power (not enough juice for laptops) http://www.voltaicsystems.com/

GPS works great in West Africa

[Anonymous Coward]

I just returned from Sierra Leone and used my GPS (Garmin etrex venture)to locate places without addresses.

Make sure the country you are going do doesn't think GPS are military devices otherwise you could be in big trouble.

Also bring a few 128MB flash drives with you -- they go for US$100. Boys are hired to run them back and forth to offices with PC as the phones and electricity rarely work where I was.

Also if you are going into the bush for any length of time, consider getting an Alphasmart NEO or rquivalent since the battery life is 700 hours (!) on three AA alkalines. Otherwise you may have trouble keeping your laptop charged if the power is on only 3 hours a week or so.

Right...

[SCVirus]

My girlfriend lives and works in West Africa
Suuure she does.

Laptop, portable GPS, rental car, google earth Pro

[scum-o]

Actually, Laptop, portable GPS, rental car (with unlimited miles), google earth pro, existing map (thre's got to me SOME roads out there), cell phone with GPRS that works there.

If you can't get the cell phone that works in that area, get some linux GPS software that just records the lat, lon and time to a file. You can run the software through a mapping package when you get back home. You'll need a piece of paper to write down the time/date you turn onto a new street. From there, you can create maps no problem.

Plot the lat/long by time, and every time that you record a street name change, the next series of dots will be on that street until the next change. Make sure that you are using the time from the GPS, not your watch or your laptop (unless your laptop is synched with the GPS or NTP or whatever).

Disclaimer: I'm not a map-maker.

Re:GPS hardware reviews @ http://gpsinformation.ne

[lscotte]

Mod parent up!

Try This Setup...

[norite]

Depending on how much money you have, This is what I would do:

Get a differential GPS system - ordinary handheld GPS can be out by as much as 10 metres. Differential will cut that error down to less than a metre - well inside the error tolerances of standard 1:1250 mapping for urban areas. Get a tablet PC, and hook the GPS to it, using a program like PenMap installed on the tablet PC - this will trace your route directly from the GPS as you walk, and you can then export this data straight into a GIS, like ESRI's ArcMap.

aerial photographs or satellite imagery will be a big help in locating where you are, but they will never be as accurate as walking it yourself with a GPS

As I see it, your only big issue will be recharging your batteries, and checking what voltage the country runs on - either 110v or 220v. When we go out into the wilds to do a survey, the GPS battery is good for several hours, and it depends on how many hours per day you plan to survey. If I were you I would double up on the battery supply, hell even triple up on it!

One final thing - AFAIK, I'm not aware of any GIS software that runs on Macs....

Don't bother with satellite pictures...

[zippthorne]

Unless they're decent quality. Try to find some overflight pictures instead. If you're mapping a small area, you could even do it yourself perhaps.

Hire a bush pilot and make several passes over the villages, say one color, one near-IR and one UV. Stitch the photos together later. Make sure you have a large diameter lens so you can use a fast shutter speed. (I think UV is what the makers of topo maps use to map buildings)

Even poor-man's aerial photography is going to be better than satellite pictures.

Personal experience.

[Anonymous Coward]

Wow, I would never have thought that particular experience would be something to post about on /., but here it goes.

I have actually done exactly that, some charting mission in West Africa with a GPS system (a good old Thales Scorpio).

If you need any sort of precision that requires differential GPS, your main concern is finding altimetric reference points. Those are HARD to find. Some knowledge of hydrography helps.

If a vertical incertitude of the order of the meter is good for you, your life is going to be a lot easier. No need to set up a differential station, etc.

To gather data, you can simply attach the GPS antenna on a 4x4, collect data on one of those rugged Husky hand computers, then transfer it all onto a laptop as circumstances allow, for processing. A professional-grade GPS system will come with its own processing software, so that's a non-issue.

The hardware held surprisingly well during our mission, but you will probably want a spare laptop handy.

If your needs require differential GPS, you will probably want to hire someone on the spot to guard the station while you're roaming the zone to gather your data. Wandering cattle pushing your station over can mean a day of work wasted.

what about a professional

[Anonymous Coward]

the fact that you play with pc and macs doesnt automatically make yourself someone that knows every discipline out there, ask someone that knows about cartography. it's a better way to help.

My 2c

[Anonymous Coward]

A cheap GPS, a car charger and Google Earth.

Low tech is good

[ornel]

Congratulations on a great project. Mapping can really empower an isolated village to better understand their place in the country and the world. I'm just back from a trip to what could be called uncharted territories in the southern tip of Panama. I a 1:50,000 map, which was last checked on the field in 1961. Since not a lot of people live here it is not a high priority for the government's mapping agency. The result is that all the names of the rivers on the map are wrong, the villages just don't appear and a lot of what shows as forest has now been cleared. The big mistake I made was not to take a GPS, but in a way it forced me to do things the low-tech way, which is good to learn when you run out of batteries in a place with no electricity and no roads to take your car and plug things in the cigarrette lighter socket. So first thing: get some free satellite pictures, check both Google Earth and Nasa's World Wind (unfortunately you need Windows for these) because you may find better images in one or the other for the part of the world you are interested in. You can also check https://zulu.ssc.nasa.gov/mrsid/mrsid.pl and maybe you can find a MrSID reader for mac to look at the pictures and export tiffs. So print the images out in colour and have several copies because those bubble-jet printouts don't go well together with rainwater. Or laminate them. Then go to the country's mapping agency if there is one and get the most detailed map you can find of the area. It might very well be a 1:250,000 one or worse, but it is better than nothing. Again, more than one copy is a good idea, one to leave intact and one for making notes on. Fold your map. This is more important than you may think, as you can fold your map to have easy access to the part you will repeatedly check and you won't have to open the whole thing in pouring rain and be too obvious about what you are doing if you don't intend to. Take a digital camera with good battery life. Not a lot of options in the "all weather" category for digital cameras, so maybe get a good regular one and keep it protected. Pictures of places and features also keep a record of the time and date you were there and may provide very good information when you forget to note it down. Get plenty large thick zip-loc freezer bags before you go to Africa (might be cheaper in the US) to put your maps and papers and GPS and digital camera in. It is maybe not a good idea to take a laptop or a Palm on the field. Humidity will probably kill it. Take instead a good Moleskine : low tech, no batteries, very reliable. Another option is Rite in the Rain. And several pencils which you can sharpen with a knife. Talk to everybody, double- and triple-check the names of rivers and other features as well as the number of houses and the population of places. Be honest and open about what you are doing. Make sure you make the finished work available to the people in the villages so they can use it.

Also very important!

[Illserve]

Color LCD displays are hard to read in the sun!

And they use more power!

It's just all bad, go with trusty greyscale LCD.

Open Ended

[satterth]

This is sort of an open ended question.

You can expect a whole bunch of answers that range from cheap to really expensive. $200 to $100,000 (or even more). It all depends on how much and what kind of data you want to pick up.

For example if all you want to do is go into some village and count monkeys, then draw a dot on a large paper map and write a number down. Then take a simple handheld GPS with you and be done. This will give you a Lat/Long or some sort of UTM coordinate that should be more than accurate enough for this purpose.

If you want to map existing roads, buildings, topo relief, rivers, farm land usage etc... then get ready to spend a whole bunch of money.

Explain what you want kind of data you want to record. As solutions will vary greatly.

Some Practical Considerations

[waterbearca]

I recently spent two years in southern africa as an engineer on a skills exchange. For what it is worth you should be able to feel comfortable with your own answers to the following.. Is what I do going to be sustainable? Will I be able to transfer the skills for others to maintain the maps after I return home? If you are bringing your own equipment, will locals have the equipment after you leave? Will locals be able to maintain the equipment / software / data ? As you will most likely apear as a well-off foreigner, how will you deal with security of your equipment?

That being said, variable power and heat are hard on gear. Look up service addresses etc. and leave the info with your reliable friend who will juggle things for you on this end.

And have fun, and be respectful. The impression you create is as important as the maps.

My experiences

[vrmlguy]

Two years ago, I made a couple of trips to Russia. I brought along an old Garmin GPS that ran on four AA batteries. Before the trip, I installed a fresh set of lithium batteries, and everytime I was someplace interesting, I'd power it up and note the coordinates. The past few days, I've been transfering that data into Google Earth and discovering all sorts of interesting things about where I was. The resolution isn't as good as in the more populated parts of the US, but there are large swatching of our country where that is also true. (Compare http://maps.google.com/maps?q=kemerovo,+russia&spn =0.290932,0.476189&t=k&hl=en and http://maps.google.com/maps?q=tiptonville,+tn&spn= 0.145466,0.238094&t=k&hl=en and see how far you can zoom in.)

Regarding some of the other threads, I don't know what Russia's post-Soviet policies are about people mapping the countryside. I didn't volunteer to anyone that I had a GPS, and no one ever approached me about it. I think that it cost $115 new, and that was back in the '90s, so I wouldn't have cried too much if it had been stolen or confiscated.

Re:My experiences

[vrmlguy]

Oops, I just checked and Tiptonville is suddenly a lot more detailed. Imboden, however, still lacks detailed coverage: http://maps.google.com/maps?q=imboden,+ar&t=k&hl=e n

This may be helpful

[denmarkw00t]

And you also might have seen it the other day, but here is a link to the Tron Light Cycles in Real Life article from here on /.

They used a GPS system along with laptops and other equipment. Its not very detailed, but it's probably worth a look.

datum

[melekzek]

If you end up using maps instead of a software, be aware of the datum http://en.wikipedia.org/wiki/Geodetic_system used in the map. Because the earth is not a perfect shape, different countries use different projections, called map datum. You should set your GPS to the same datum as the map you are using.

GPS Watch out for the trees

[softcoder]

Remember too, that GPS to work must have a clear view of the sky.
Even in moderate forest, the signal can be so degraded by foliage that the receiver cannot 'see' the satellites.
If your village(s) are mostly in clearings you are prob OK, but if there is a lot of 'jungle' foliage covering the area, you could be in trouble.

my experience - Pismo+Deluo, or eTrex in pocket

[xeno]

I was going to let this alone and perhaps let the geocaching or other GPS gadget freaks answer it, but some of the discussion regarding durability and suspicious behavior by westerners leads me to throw my US$0.02 in.

It depends whether you're going to be walking or driving. I have had very good car-based mapping experiences using an older Mac, namely a G3-500 Pismo. I have found the Pismo and similar Lombard/Wallstreet units to be cheap, very functional, unobtrusive, and very durable -- almost to Panasonic Toughbook standards. Though I use both Mac and PC on a regular basis, ease of use pulls me to the Mac for GPS tools. I use mine with a remote usb-connected-and-powered Deluo GPS unit, which mounts on the dashboard or on the roof of the vehicle using a magnet on the bottom. The Deluo has no display or blinky lights to advertise its presence; it's just a 3cmSq bump with a cable. Get a car charger to keep the Mac powered up, use the nifty Control+Alt+Apple+8 to switch the display to "7337 mode" (inverse greyscale display), and you'll be about as unobtrusive as you can get. Less obtrusive than simply being a western guy in rural west Africa, anyway.

On the other hand, if you're going to be on foot, I heartily recommend ditching the laptop and taking an eTrex Voyager or similar model. It's very durable, gets good reception, fits in your shirt pocket out of sight while still receiving a signal, and runs all day long -- thanks in part to its black and white screen -- on two AA batteries. Make a list on paper of waypoints you expect to see, mark them on the eTrex unit using the little joystick when you get to each spot in sequence, and then put it back in your shirt pocket without making a scene. Take a few sets of rechargable AAs and a solar charger, and leave the computer at home for data dumps at the end of each day.

Better yet, take two or three eTrex units (US$60-90 used), and consider them disposable -- expect to have them all eventually stolen from you or seized by various police or military. You may face less hassle and risk if you appear only mildly irritated that a trinket is being taken, as opposed to hyperventiating over someone taking all your data. Eventually you can take the downloaded data and correlate the traces and waypoints using satellite maps or other starting points.

J

Keep it simple

[NMBob]

If you are just going to be marking the location of a whole village then just about any handheld unit will do, like from the companies Garmin or Magellan. If you are going to do individual houses they would be cutting it close. If you need accurate, sub-meter range, measurements, then that is a whole 'nother universe, and you'd want something from the company Trimble. If you want to make maps, like of "streets", in the villages on the GPS you are in for a bumpy ride. If you just want to plot data points on a map after you've collected the data then a handheld should do. I don't think Garmin or Magellan (or Trimble) have any good maps of Africa that you can load into their GPSs. Cities and stuff might be OK, but not much in the country. Get the data -- worry about maps and plotting it later. You can do things like scan paper maps into products like OziExplorer on a PC and plot your recorded data points in just about any way you can imagine. I've had several Garmin GPS receivers and they've never let me down. I've used them everywhere in places like http://www.greschke.com/passcal/antarctica/ant25.h tm As a bunch of others have stated, GPS will work everywhere. Bob

Go Solar

[rocker_wannabe]

I have been to East Africa (Kenya and Uganda) and they probably have more reliable electricity than much of Africa, which is to say that it's all fairly bad. I talked with people who have tried to travel with laptops in Africa and it's very frustrating.

If it were me, and I would love to go to West Africa if you're looking for someone, I would take a couple small solar panels and some rechargable batteries. There is usually plenty of sunshine. It shouldn't take long to charge up NiMH type batteries, which is the only type I would bother with unless you have access to more exotic batteries. My kid's GameBoy Advance SP game take 3 hours to charge and runs for 11 hours with the backlight on, according to the spec. Coming from the bad-old NiCad days, I was very impressed with that.

You might start with this link: http://www.energyenv.co.uk/Laptop_Chargers.asp

Religion that God our Father accepts as pure and faultless is this: to look after the orphans and widows in their distress and to keep oneself from being polluted by the world." James 1:27

I think you're in over your head

[Nom du Keyboard]

does GPS equipment from the US work over there?

I think if you need to ask this question then you're in over your head because you clearly don't understand the system.

As has been pointed out by others, you should know what power is available over there to run your laptop, and carry enough batteries for your GPS. Most aren't rechargable simply because they can run for 10's of hours on penlights.

And don't rule out considering a car charger for you laptop, since whatever vehicle you end up using may be more compatible -- and reliable -- than the wall plugs.

Power suggestions...

[BackInIraq]

In addition to a solar-powered battery charger for your GPS, I'd also recommend a power inverter for your computer gear, or anything else that might need 110VAC. Assuming, of course, you are going to have a vehicle handy. Something in the 300W range should do you just fine, and shouldn't be horribly expensive.

And, of course, everything you take you'll want to have extras of...GPS's, chargers, inverters, possibly even a second laptop. Not like you can go to Radio Shack and pick up a replacement, or have one shipped overnight :).

Re:Power suggestions...

[timeOday]

I'd also recommend a power inverter for your computer gear, or anything else that might need 110VAC. Assuming, of course, you are going to have a vehicle handy.

But you don't want a power inverter to run a laptop off a car, just a DC adapter. No point converting DC->AC->DC.

Re:Power suggestions...

[magarity]

possibly even a second laptop

For the price of two regular laptops, get a Panasonic Toughbook. It will still be useable after exiting the far end of the digestive tract of the alligator that eats you.

Re:Power suggestions...

[BackInIraq]

But you don't want a power inverter to run a laptop off a car, just a DC adapter. No point converting DC->AC->DC.

Unless you have multiple 110VAC devices, in which case instead of needing multiple DC adapters you can just get an inverter and run them all.

Re:Power suggestions...

[BackInIraq]

For the price of two regular laptops, get a Panasonic Toughbook. It will still be useable after exiting the far end of the digestive tract of the alligator that eats you.

Are you kidding? I'm writing this from a Panasonic CF-29...you could close it, beat the alligator to death with it, open it back up, and continue working. They're pricey, but great computers.

And yes, if one has the money for it, I would heartily recommend one of these for such a trip.

Re:Power suggestions...

[bruce_the_loon]

So, you're not planning on getting further than Florida are you. Dang under-educated Americans.

Re:Power suggestions...

[davekebab]

The ruggedized pissonic

It weighs more than a desktop, it uses the same technology that fills pamela anderson and I bought one. Biggest mistake.

It survived Africa but when the thing screwed up Pissonic wouldn't fix it under guarantee BECAUSE I HAD BEEN ROUGH WITH IT!! Light scratching actually but they have diabolical tech support and resellers from hell (also unavailable in Africa)

My advice. Buy two or three laptops on ebay and one of those bulletproof lacie drives. Give the old ones away when you leave.

I haven't bought anything pissonic since!

DK

panasonic ruggedized toughbook laptop notebook review evaluation

That is NOT low tech!

[GrahamCox]

Satellite images, digital cameras, GPS, colour printers.... how on earth did mankind ever manage mapping in the 16th century? A decent theodolite, a compass and some painstaking triangulation are all that you really need. Now THAT's low tech. Seriously, the older techniques are still perfectly valid and useful - ask any surveyor.

If you find yourself....

[Anonymous Coward]

standing in a grassy field that goes on in every direction:

North, South, East, West, Northeast, Northwest, Southeast, Southwest, Up, and Down.

You might want to try using graphing paper...

Oh and try not to wake the dragon... ;-)

GPS & Mapping

[Anonymous Coward]

Ive been playing with my GPS for a few months now and Ive only gotten really excited about it this past week when I purchased Google Earth Plus. I use a Magellan Meridian Platinum (http://www.magellangps.com/en/products/product.as p?PRODID=1) , though you probably wont need all of the extra features this model provides. Google Earth Plus (http://earth.google.com/) can download information from both Garmin and Magellan (most models) GPS devies and map them instantly. For a few examples images visit http://1101001.com/

Mapping villages in Madagascar

[burning_plastic]

For most of 2003 and 2004 I was working in rural Madagascar on a reef conservation project (as Diving Manager, Scientist and general tech guy).

We primarily used handheld GPS units (Garmin, Magellan) for mapping the outlines of the reefs. This was accomplished by attching the GPS in a waterproof bag to a float and towing it behind a diver. It was fairly effective, and provided data good enough for GIS work.

We also mapped the roads (read: dirt tracks) and trails in the local area, but the part that seems most approprate to this discussion was mapping the local fishing villages for socio-economic research.

We mapped out the main roads, the major buildings, and all of the houses that we interviewed people at so that we could build up a full profile of the village for input into our GIS work.

For most work, the most basic GPS units were fine (eg. Garmin Etrex, and 7x series - we also used a couple of Magellan and Silva units). Use rechargable NiMh batteries as although they don't last as long as alkalines, you can use a solar recharger to give you an endless supply. (As an aside, only the Garmins were able to run on the crappy local batteries).

As an idea of where we were - the nearest phone line was over 200 miles away, and the only reliable method of communication was satellite phone (radio messages could sometimes get through via several mission relays, but if the weather was off then no chance).

I used a couple of fairly old (P2 233) Toshiba Satellites as my data machines as they could take a beating and keep working (and were free). (Win 98 on both and a dual boot to RH 9 on one)

Hope this helps...

Dan.

Get a printer

[Bazman]

Hard-copy is more reliable than hard disk or GPS RAM. If this data is costing you a packet to collect, and going back to do it again is not an option you want to have to explore, then get your coordinates onto paper as soon as possible. Print several copies and post some of them off. If you do lose your digital data, its cheaper to get it retyped or OCRd from printouts.

My GPS glitched three times in Morocco - possibly the dodgy power in the Land Rover. On the third time the reset cleared the memory. I lost the waypoint I was heading for, as well as all the stored locations I had.

I re-entered the waypoints from a book, and we were on our way again.

Yes, paper can burn, get soggy, get lost, get eaten by rodents - but then so can computer hardware.

Baz

These satellite images and software

[Lord Satri]

Interesting challenge. To complete what MathFox was saying about satellite imagery, he's right, it can help a lot. However, the main problem can be spatial resolution:

Landsat-7 is available freely and cover the whole world, but it's only 15 m (panchromatic) and 30 m (multispectral)

ASTER L1B is also free but the cover is not complete. It's very good data with 3 bands in VNIR. 15 bands total.

SRTM-DEM, for topography, is also great and free. 3 arc-second of horizontal resolution and about 5 m vertically (relative, not absolute). It really is useful data for topography, and it's free.

Where to find this data? Start on my Remote Sensing Table http://www.matox.com/agisrs/arsist

As for software, yes, GRASS GIS works fine on MacOS X, *but*, the learning curve is very steep. I don't know MacGPS Pro. See the two other comments http://ask.slashdot.org/comments.pl?sid=155849&cid =13067619 and http://ask.slashdot.org/comments.pl?sid=155849&cid =13067710

If I were you, I would try to ask somewhere else than /.. Nothing against the /. crowd, it just doesn't hurt to have a second opinion, especially if it comes from GIS/RS experts. You can try the Applied-GIS-RS mailing list http://www.matox.com/agisrs but there are a lot of other groups of GIS/RS specialists. Good luck!

Re:These satellite images and software

[Anonymous Coward]

just a few comments!

-> ASTER is not completely free, but it's close - and it's definately worth the 'handling fee' - especially if you need newer images than you can get from Landsat

- As for software you could try CHIPS (http://www.geogr.ku.dk/CHIPS) for windows - it's free and will do all the basic stuff. It also includes a GPS interface so you can upload and download data from most handheld GPS's. It also do live plotting of your location from a GPS.

Cheap mapping

[Mimico]

First on the Power issue: If your can get GPS receivers that run off 12VDC batteries you can always charge them with solar panels. British Petroleum made the panels we use but they have quit that business (they realized they're in the oil business)but hardware stores now have fold-out panels for boating and camping that could do the trick. I'd talk to a dealer about hooking up the panel to a charger instead of direct to the battery to prevent damage.The company I work for use older Novatel DL receivers that run off 12vdc 7amp-hour batteries that can be bought at stores that sell wheelchair or security system batts. I don't recommend the DL system though- it's heavy and cumbersome with no interface to speak of and not supported by Novatel very well. Trimble equipment is tough and designed for this type of work but is expensive. Get a 10-foot pole and stick your antenna on the top with the receiver in a bag or around your neck. You can then take shots by placing the other pole end on the feature or trace at 1 second intervals as you walk trails without signal interference from ground vegetation (I assume there are few trees around those parts)and you should get accuracies to about 10 metres. For the mapping side of things try this: http://opensourcegis.org/ I've never used anything other than ESRI GIS products such as ARCINFO but all you really need is some free CAD software that imports ASCII geographic coordinates.

Have you considered 'old skool' methods?

[Anonymous Coward]

I'm not sure what your level of technical expertise is, or what your access to equipment is. However, have you considered using optical surveying methods (plane tables and alidades, a total station, or failing that, a tape, a dumpy level, and a grade rod)?

These techniques are relatively (except for the total station!) inexpensive and HIGHLY accurate. It's fairly easy to get sub-meter accuracy with a good measuring chain and a compass, and most modern total stations are in the centimeter range. And it's probably easier to find replacement equipment (again, except for the total station) for optical instruments than it is to find a new GPS in Africa. Not to mention the fact that they are fairly simple to figure out.

What level of detail do you need? Will you be doing topographic surveys for utility or road development? Or is this more for cultural heritage purposes? Will you need to map at multiple scales at differing resolutions (i.e. site scale versus archeological trench scale)? What does the final product have to look like? How much time/money do you have to spend? You need to answer these questions before picking a mapping method.

My (Not So Humble) Recommendations

1) Get a basic Surveying textbook. Learn about the strength and limitations of the different traditional methods of surveying. Make sure you have the background to deal with Recommendation 2.

2) Sit down and answer the following questions:
* What do I have to produce?
* What accuracy do I need?
* How fast do I need it?
* How much can I spend

3) Even if you take a GPS, make sure to take the following equipment with you as a backup:
1) Survey chain or fiberglass tape (100 or 300 m will be good)
2) Survey compass with clinometer (Brunton or equivalent)
3) Marking implements (sticks, pinflags, nylon flagging, etc)
4) Grid paper and pencils. Get a series of Write in the Rain (tm) Transit notebooks; they are ideal for recording both survey data, sketch maps, and field notes.

My two cents

[Sylver Dragon]

1. GPS works anywhere in the world where you can "see" enough satellites. Depending upon terrain the accuarcy will be better or worse.
2. Trimble makes some cool GPS units, which can be put through some rather rough conditions and not have a problem.
3. Consider a ruggedized laptop. It will cost more and won't be as fast, but it will stand up to the abuse you will inevitiblly put it through. No kidding, we had one get dropped in a lake by accident, it is still functional.
4. As for the software, the people I work with use ArcPad from ESRI. Along with the rest of the ArcGIS stuff. It's pretty nice, but expensive.

Geocoding

[Anonymous Coward]

You sir, are in luck.

I'm a special projects programmer (read: code monkey who has to make stuff work that was due yesterday), and I recently researched the living hell out this very problem.

Geocoding is the keyword here thats really worth a google. Basically, it should be noted that in the majority of the world, avalible geocoding data sucks.

Ireland is an prime example. Only about 30% of the transportation networks are geocoded.

That being said, what you should really get is a good geocoding kit (I have a link to the hardware at work, which ill post if there's intrest). It might be overkill, but take it from me, the information you gather with it is worth a freakin lot of money.

Some links:

http://www.travelbygps.com/authoring.php

http://www.opengeospatial.org/

For Example

[bperkins]

The following data was taken by my Magellan Sportrak Map while geocaching in Rock Rimmon State forest, superimposed on google maps. It shows the drive there, the walk in the woods, and part of the drive back.

http://throb.netspace.org/~bperk/demo.html

The data on the drive was better than I expected. I think the trees prevented the data from being as good on the hike, though you can see the clearing at the top of the hill near the cache in the satellite image (near Long Pond).

This would indicate to me that the data from this ~$200 GPS would be usable for some fairly decent mapping without an external computer. Since the track memory is limited to 2000 points you'd need to download from time to time.

Some free solutions

[nadaou]

Hardware:
Get a Garmin handheld GPS with a 12v adaptor & download cable, and probably a crate of AA batts.
Stick with consumer stuff. Buying a spare or 3 is cheaper than buying a Trimble survey grade and they all work well enough.

GPS Software:
Download GPStrans &/or GPSbabel.
http://gpstrans.sourceforge.net/
http://www.gpsbabel.org/
You can load the GPS waypoints/track/routes into a mapping format with GRASS GIS's v.in.garmin or gpsbabel+anything.

Mapping software:
Use QGIS. http://qgis.org/
Use GPS plugin.

Data:
Start by downloading SRTM elevation data and VMAP0 digital chart of the world data. Best there will be publicly available for Africa.

Instructions for converting into a usable format here:
http://grass.ibiblio.org/newsletter/GRASSNews_vol3 .pdf

Import and crop with GRASS GIS (r.in.srtm and v.in.ogr modules) and either use with QGIS directly or export into a secondary more popular format for use with other software.

GRASS works well on a Mac. http://grass.ibiblio.org/

GPS interface programs should work on a Mac, GPStrans is command line only so with some hacking and GPSbabel is well maintained so there should be a Mac port by now.

SRTM: http://www2.jpl.nasa.gov/srtm/
VMAP0: http://www.mapability.com/info/vmap0_index.html

Re:Some free solutions

[Anonymous Coward]

Nadaou is on the right train of thought. If I can offer the following:

Hardware
Stick with consumer Garmin, etrex units are small (easy to conceal), easy to use and affordable.

Software
Consider ESRI's free ArcExplorer. It supports MANY data format, very simply to use, and is cross platform.
http://esri.com/software/arcexplorer/index.html

Data
I highly recommend Landsat satellite imagery, specifically Landsat GeoCover 2000. It is free, global coverage at 30 metre resolution, compressed, yada yada, trust me, it is exceptional!
Get it here:
https://zulu.ssc.nasa.gov/mrsid/
http://glcf.umiacs.umd.edu/portal/geocover/earthsa t.shtml

These MrSID wavelet compressed images can also be viewed using a free geoviewer from LizardTech:
http://www.lizardtech.com/download/dl_options.php? page=viewers

Do as much prep work at home before going over there. I would suggest printing maps with UTM grid on them (this is the grid that the GPS can tell your position in) - I've always found this more useful then Lat-Long (how far away is 7 seconds?!?). Essentially build one map at a good logical scale like 1:10,000, then PAN & PRINT, PAN & PRINT, repeat as necessary.

Re:Some free solutions

[cedric77]

Nadaou talked about SRTM datas. Their resolution outside USA is 90 meters which is maybe not enough for you. You can try to get ASTER data (Digital Elevation Model of 30 meters resolution) to complete SRTM locally, however with less quality (there are no post-treatments on them), and a very very reduce coverage ...

Currently the coverage is of only seven DEM on Ghana.
But maybe it's the geographical position you are looking for ...

An article from John Childs presenting quickly ASTER format
John Childs also explains how to obtain data from the "EOS Data Gateway"
Homepage of ASTER

--

Cedric

Kite Aerial Photography

[Anonymous Coward]

I think you could include a home-brew Kite Aerial Photography setup. You can transport the kite dissasembled and as far as map making, it could be better than satalite photos of the area.

Have you ever heard of a method called resection?

[olivercromwell]

Reptski, a compass CAN tell you where you are, wehn used in conjunction with a topographical map. It is the oldest, and still most accurate method of determining your position. Take a toppo map. Orient it to the ground (that is, use the compass to determine north, then orient the map accordingly). Choose two or three prominent physical features. Take a compass bearing to each. As you take the bearing, use the edge of the compass to draw a line from the feature back along the bearing. For this, the compass needle will need to point north, the compass itself then acting as a protractor, as the bezel has been set to the bearing. Do this a minimum of twice, three times if you want your position withine ONE meter. Soldiers in armies around the world are taught to do this every day of the year, and it works.

You're surveying, use surveying gear...

[Goonie]

As previous posters have pointed out, what you're doing is surveying/cartography, so if you can possibly afford it you want proper surveying/cartograpic gear. Surveying GPS's are made by companies like Leica and Trimble, cost a lot more than your Garmin bushwalker's jobby, and are accurate to within a few centimetres. That's what you really want if you're going to try to make real maps.

Turning Off GPS or Selective Availability

[billstewart]

The US government would almost *never* consider an emergency severe enough to turn off GPS, except possibly an incoming nuclear cruise missile. That's a really extreme case. What they might do, if they were very upset about something, would be to toggle the Selective Availability switch, which reduces your GPS accuracy to about 50-100 meters instead of 10 meters (enough that a nuclear missile is unlikely to precisely hit the lid of a missile silo or other heavily armored target), but even that's very unlikely these days. And they can set that differently in different areas, so even if it's turned off in Iraq, it'd still be ok in Ghana.

Since you're talking about charting villages in Ghana, worst case is you'll have a 100 meter uncertainty in their locations, which is probably still much better than you have now. More likely you'd have a 5-10 meter uncertainty, and you'd have a similar uncertainty with nearby landmarks (so if the village is next to the river, they're both uncertain by 10 meters but you can see where the river is.)

Re:Turning Off GPS or Selective Availability

[Anonymous Coward]

No one uses GPS to guide its' nuclear missiles. For one thing, GPS is controlled by the USA, as you mentioned. Tactically, nobody attacking the US would want to give navigational control to the Americans. I highly doubt that even the US uses GPS tech to guide its' missiles, although I really don't know that for sure. GPS was still in its' infancy when nuclear missile tech was in full swing... I'm sure anyone who had the capabilities to manufacture a nuclear missile also has the capabilities to guide it using a non-gps method.

MacGPSPro

[Anonymous Coward]

I would like to take this opportunity to highly reccomend MacGPS Pro

It's small, cheap, well-supported, and can import and calibrate a wide variety of file formats and map data. I've used it extensively as a hobbyist, but I know people who have used it in applications as diverse as wood-rat population monitoring, and civil-war archaeology.

Route saving, local troubbles

[dindi]

Unless you have professional GPS devices, I recommend a consumer one (which is a few meters accurate if you have clear view.

Make sure you have big memory for saving routes, otherwise you will need a laptop/pda connected all the time...

You can find lots of free software to make maps, if you manage to get satellite images you can make your own map (GPSU and others will calibrate known map points to your route).

It all might sounds easy, but it is harder as it sounds. Sometimes you loose reception so you have to go back to re-record or you have to connect points by hand with a software ...

I got sick of the local Costa Rican tradition of not having maps and having directions like :
100E 50N from Whatever Pharmacy near McDonalds ...

So i bought an etrex vista and started making my maps ... well saving routes is a thing, but never really got the time to convert them to actual garmin format maps.... but one day :)

anyway good luck for the project !

We don't use 120 VAC

[Anonymous Coward]

Remember, the current is AC. The voltage is too. Sometimes there is zero voltage. Sometimes there is Pi voltage. There are a few different ways of expressing something like this. There is the difference between the peaks, RMS (root mean square), etc. 110 is just as correct as 120.

Re:We don't use 120 VAC

[petermgreen]

RMS is the standard for power voltage measurement PERIOD.

as for 110V vs 120V i belive the idea is that 120V is the nominal supply voltage and 110V is the nominal utilisation voltage with the remaining 10V being an allowance for volt drop in wiring. i don't know how this works out in practice though.

GIS

[Anonymous Coward]

Your best bet with software is some kind of GIS suite (geographic information system). I have used GIS with GPS data at work, but only on small lakes and such. ESRI GIS is fairly industry-standard, but I am still learning it and I am sure there are much cheaper (and GPL'd?) alternatives out there. I would also recommend obtaining some satellite photos for tracing structures (it takes a lot less time that way, trust me).

That's *developing*!

[Provocateur]

Not undeveloped, you insensitive clod!

Region coding...

[jemenake]

My girlfriend lives and works in West Africa and on my next visit...

You travel to Africa to get to your girlfriend?!? Dude, either you are TOTALLY pussy-whipped, or she's totally hot and you're a genius for getting her away from any potential competition by sticking her out in the boondocks. ("A 'bird' out in the bush is worth two in a developed country', I guess they could say).

(does GPS equipment from the US work over there?)

Fortunately, the Motion Picture Assoc. of America didn't forsee GPS's ever being used for any kind of movie viewing... so they didn't press to get region-coding into GPS's, like they do with DVD players. :)

"My Girlfriend..."

[The Blom]

Quote: "My girlfriend lives and works in West Africa..." Oh Yeah... "My old girlfriend from Oklahoma was gonna fly out for the dance but she couldn't cause she's doing some modeling right now." ... ND

Laptop-only or Standalone with GUI (both!)

[billstewart]

If you're always going to use the GPS with your laptop, then you can simplify things and use a cheap laptop-only GPS. The ones I've seen generally don't have a built-in user interface - they send coordinates and timestamps to your PC, and let your PC deal with the user interface. They used to be serial-port interfaces, but now they have USB which provides electricity as well as a data interface, so all you have to do is power your PC (which is pretty easy if you're driving a truck everywhere you go, but not the right choice if you're walking a lot and don't want to carry it.) There are also PCMCIA-card versions that fit into the PC directly.

Most standalone GPS's these days, except for the very cheap ones, do have PC cables as well as built-in user interfaces, so you can get the best of both worlds, but I don't know if they can run on USB power or if you'll need to mess with lots of rechargeable batteries.

Of course, if GPS is important, you need a spare one anyway, so you might as well bring both. They're fairly cheap here, so you may consider leaving one behind as a gift if it doesn't get broken, stolen, etc. while you're using it.

Re:Laptop-only or Standalone with GUI (both!)

[fshalor]

Along this line, you can also use a iPaq or Palm with a CF card and a CF gps. May save on power overall.

But I'm a fan of the etrex or trimble devices. We have a few handlheld GPS's, but do most of our major maping with the Trimble device. It makes great shape fiiles, and they (with a little hacking arg..) go right into our gis maps.

There's a 3-D option for OziExplorer

[ivi]

Dunno if you'd collect enough altitude data points
to find the result useful, but just to let u know.

suggestion

[VonSkippy]

"some resources that would help me out?"

Get GPS (Girlfriend Potential Sensor) Unit.
Find Local Girlfriend.
Enjoy.

Garmin Solution

[knuxed]

One way you could do it is to couple a GPSMAP 60 from Garmin or any other cheap Garmin GPS receiver and hook it up to the Garmin MapSource Program or GPSMapEdit by either serial or USB.You get to save all the POIs and waypoints and even render vector maps which are much better than the normal maps.The only problem would be is the maps would only be Garmin receiver compatible.

GPS receivers

[Anonymous Coward]

You could always try a GPS Sensor (like Garmin OEM18). I think these have a USB option, so power is not as much of a problem. It just delivers lat/long info to any NMEA program/device I think.

village mapping

[neonsignal]

Depending on the purpose of the maps, it might be better just keep notes of where places are with respect to geographical landmarks, and use a satellite image to place them when you return from location. Once the coverage of the world (eg google satellite maps) is detailed enough, you'll be able to locate individual huts! For example, in a remote area (no power, 2 days walk from the nearest road) that I lived in for a couple of years in Papua New Guinea, I can locate the rivers and crop areas, and then figure out the location of the villages. I'd also be surprised if there weren't already topological maps with some villages marked that you could add to. Or is that sort of thing classified in the USA? :-)

Falconview

[Gumpmaster]

I would recommend the program falconview (http://www.falconview.org/) if you can get a copy of it. It handles all sorts of maps and can even export to GPS. The military uses it in all sorts of undeveloped countries.

GPS is nifty but also use paper and take pictures

[PedroGeoBass]

Having mapped extensively in sketchy places, I would suggest that you take the most important advice from above: (to recap)
1) Get as many maps/photos as possible 2) Learn to use them, and their problems (Perspective, warp, datum calibrations)
3) DEFINITELY pay attention to local customs, starting with whoever has the guns.

ADDING TO THIS:

1) When you take a GPS point, do yourself a favor and **WRITE DOWN THE DATA ON A PIECE OF PAPER**. And I mean when you take the point, not at night around the 'campfire'. When you GPS dies, your laptop gets taken or drops in a stream, you still have your data. Sorry, but tech is cool, but computers fail way too often. (Or gets stolen). A side note, make sure you take detailed notes as to which point is what. This is THEE most common mistake in all mapping.

2) TAKE PICTURES OF YOUR MAPS, digital or film, ESPECIALLY before you go through customs. If you can, mail them to yourself back home. This saved me a field seasons worth of data one year.

3) And have as many permission letters as possible. Also, have it physically rubber stamped as much as you can. Makes it look VERY official. Believe it or not, this works.

4) I CAN NOT agree more with those who have warned that maps will get you killed, in some places faster than your religion. On this tip, take as FEW maps with you as possible. Make sure they are compact and tidy. But DO NOT purposely conceal them. This makes you a spy.

Oh and if your working in Turkey in the future, the words "Gisli Secret" at the top of your cute little topo maps means "Top Secret", and the military can read.

GPS Accuracy

[Anonymous Coward]

I only skimmed through a few of the posts, so don't blast me for being repetitive. (Like you could ever hurt the feelings of "Anonymous Coward" anyway...)

As a co-op for a nearby municipal power company, I am currently involved with a program that involves GPS. The relevant part is that we are recording GPS coordinates for every location where we have equipment - poles, pad-mount transformers, and so on.

Two major concerns were cost and accuracy. We didn't need the best accuracy possible, and it was out of our price range anyway. On the other hand, the inexpensive units would only guarantee accuracy to within several meters. That was not nearly accurate enough - we wanted something that promised accuracy of about 1 meter. From what I read and what I was told, to get that level of accuracy you need more than just a single receiver - you need at least one receiver at a known reference point. The stationary receiver should be located where you already know the exact coordinates, and it should be relatively close to where the roving receiver will be recording - say within 50km or so. At the end of the day you would download the recorded data from both receivers, then a program can analyze the data, usually resulting in sub-meter accuracy. We were somewhat lucky in that the county operates a [CORS] receiver that is plenty close enough, and the data is publicly available on the web.

There are a couple of other slightly different options for improving accuracy, too. Instead of downloading the data to a PC at the end of the day, the receiver may be able to receive a signal that is broadcast from a nearby reference. The receiver can use that signal to improve its measurements on the fly. Depending on where you are in the world, the signal is broadcast differently, but it achieves the same goals.

The last - but most important - thing to note about accuracy is the terrain. To obtain really accurate readings, the receiver needs a clear line of sight to several satellites. At least three are required to get latitude and longitude, and at least four are required to get altitude as well. More satellites means better accuracy, in general. Also to be considered is the satellites' positions. If the satellites the receiver is tracking are all in one part of the sky, the accuracy is less than if they were spread out. (I expect that most Slashdotters could figure this next part out, but I have decided not to assume anything.) What this means is that receivers work best in an open field. Near buildings or in dense vegetation the accuracy can degrade quickly.

-

I am not here to plug brands - I could care less - but I will share what little I know. I noticed one recommendation for Trimble - they are supposed to be good, but the receivers I saw were pricey. The unit we eventually settled on is Thales Navigation's MobileMapper. As long as you are not actively trying to destroy them, they work great. The PC software leaves a bit to be desired, in that it's not always easy [or even possible] to get it do what you want. As far as accuracy is concerned, after processing the data on a PC, almost all of the points have accuracy estimates less than one meter. A very few points have had terrible accuracy estimates, but those can usually be attributed to nearby buildings. Overall, we have been pleased with the results.

GPS

[tsilb]

I don't see why not. I bought a Garmin and it worked in Japan. There just isn't much data available overseas.

local sensitivities

[quick_dry_3]

as others have said, it would be best to seak advice from your embassy in the countries, and if advice from poepl in the area about anyone who may object to you carrying a GPS around.

Beyond that, I'd say do it covertly, do you actually need to have your GPS out so you can read from it all the time? just stick it and pocket pc in your backpack and have them logging position into a simple database, then later on you can use satellite pictures to get detail.

I do this from the car to then make moving maps of cruises my car club goes on using google maps.

Integrated GPS, Compass, Camera, Laser Distance M

[Greevis]

Undoubtable the most flexible device out there for Mapping is http://www.surveylab.co.nz/Who_is_ike~qu.html/IKE by http://www.surveylab.co.nz/Surveylab.
This device allows:
o Capture of Points the user can see but not access
o Georeferenced Photos (also stores the user's compass orientation using the inbuilt compass, which is not a 'fake GPS compass BTW)
o Includes and integrates with ESRI's ArcPad GIS software, which is all but industry standard.

All in all this is a map makers dream.

First step: find the maps that already exist

[Anonymous Coward]

There is very little "uncharted" territory in West Africa, despite our misconconceptions. However, what you find will likely be old, or of poor quality, or just plain wrong or confusing. (Your map won't be much better in a few years either -- see below.)

So first step, go ask around for some local maps. Try the office of mines, or whichever gov't agency handles natural resources. The colonial powers did some pretty thorough geologic surveys, and these maps are still in use in many places, and may have even been updated in certain areas. Expect to pay a few dollars for photocopies; originals may be rare, and they might not let you touch them. If you are lucky, you might get some decent reprints. Other agencies/embassies will have maps as well, but you have to ask around.

Now, for the quality problem. No, many villages won't be listed correctly, or in the right place, or at all. This is just a fact of life in rural west africa. Village names change. Languages even change slightly. Villages are built, burn down, move, change, etc. Families move, start new villages, etc. And with illiteracy as it is, you can't get 10 people to tell you less than 4 names (that you can write down and spell) for a given village, and this holds for villages ranging from a few dozen people to hundreds. And if you come back in a decade, the pronunciation might have changed, or you just end up asking the wrong ethnic person to pronounce it, or whatever. And sometimes it feels like the trails (aka roads) shift with the seasons.

All that said, for my personal use, I made lots of maps of my local area when I lived there, just using some geological maps as a base. Easy enough to pick out features, no GPS needed. They are probably outdated even now, less than a decade later.

And a hearty second to the big warnings above! Uncle Sam wouldn't take kindly to you poking around a military base or power plant with detailed maps and a GPS. The local authorities may be VERY suspicious, so you might like to keep your maps to just, say, the very most rural of areas, and keep them inside in your own house.

-kev

Re:NO!! (Maybe)

[Anonymous Coward]

Note that a compass, sextant, and a reasonably good clock/watch would be what you really want. Other than the watch, no batteries needed. It does take some skill to use the sextant accurately, but it can be used rather well. (Within less than 1 minute of arc error is realatively easy.) There are also some pocket sun-dial/sextant devices from the old days that are rather good if you only need +/- 5 minutes arc. They fold up to about the size of an old, large silver dollar. (Much smaller than a sextant but that size difference means that it is hard to be even close to as accurate) GPS will work everywhere (albeit you need batteries and view of the sky) and it will give you everything but compass points (unless you move a lot in order to get a multi-fix triangulation) A small pocket GPS that lets you save and name waypoints would be best - you can then download those later. Most of those units will give you multiple hours of operation and if you don't need it all the time but just when at target locations, this could give you many days of use on a set of standard batteries.

compasses & vehicles don't mix

[tomkagai]

Be very careful using compasses anywhere near steel objects, like vehicles. Steel objects acquire the earth's magnetic field orientation when left stationary for any length of time, so you need to get far away from them when using a compass or your direction reading will be skewed. Digital compasses that are MOUNTED in vehicles CAN work beacuse they have a calibration routine that subtracts the field given off by the vehicle- at least until they are parked for a long period of time. Then they need to be recalibrated. In other words, don't use a hand-held compass in or within 2 meters of a vehicle. You'll get lost.

Re:compasses & vehicles don't mix

[ckaminski]

Or the famous (in our family) story my father tells of him and his father hunting one year, and getting lost... going around in circles... because pappy was taking compass readings at waist level... near his belt buckle.

Doh!

Go to www.digitalgrove.net

[Anonymous Coward]

http://www.digitalgrove.net/ has a huge collection of reviews and links to freeware for mapping, GPS, GIS, data sources, etc.. You'll get better direction and advice there than anything I've read here.

Problems and Solutions:

[VectorSC]

Problem 1: Power Problem 2: Ruggedness Solution 1: Get a car inverter. Many of the overseas autos you'll be using will have a power accessory pack that you can plug in to. Problem reduced. Also, bring enough batteries for your gear to kill one of your Camels. Solution 2: Get a Panasonic Toughbook off of Ebay. Like a CF-72 or CF-28. And then get a stack of batteries. As for the GPS unit, just get something with a good computer interface, and there you go. Magellan, Garmin...who cares? As long as you have that car charger and that stack of batteries. Thar ya go.

Plane Table and Alidade?

[LauraLolly]

There's a lot you haven't said, and there are some key questions that need to be asked.

1) Do you have any experience with mapping? Knowing how to use mapping or GIS software does not make you a good mapper. I'd much rather work with a plane table and alidade map that was correlated with satellite photos by an experienced mapper than with a GIS file that was put together by someone who had no idea what they were doing.

2) Have you researched mapping rules and laws with the local embassy? Have you contacted the State department country desks for the various countries you will be visiting? I had a geology professor who had to smuggle maps of the East Anatolian Fault in and out of Turkey, because they gave too much detail of the terrain in a politically sensitive area. Are you willing to take the risk? Now, with kids, he wouldn't risk Turkish prison.

3) Do you know power availability where you will be mapping? A very good source of reviews of solar power chargers and other portable power is the ARRL - Ham operators can't operate without power of some sort for very long. :)

4) What sort of mapping will you be doing? Physical mapping? Population mapping? Disease mapping? Economic mapping? Geologic mapping? Manmade features mapping? Get the proper contact for your sort of mapping. Keep that contact in that country in the loop. You want this person on your side.

Handheld GPS

['Talia Mastino]

I've worked with a couple models of Magellan handheld GPS units, and have ended up happiest with an inexpensive Garmin eTrex. In terms of ease of use, the eTrex wins hands-down. Not as feature-rich as many models, but performed well for what it does.
My experience comes from their use combined with K9 Search and Rescue, primarily from a training standpoint. Amazing how much you can learn about scent by overlaying the track recorded by the handler and hound and the track recorded on the "victim"'s GPS on a topo map of the area.
I also used it to map a series of logging trails in a large wooded area in which we regularly trained, with a reasonable level of success.
My experience has been that none of the lower end ($300) units do well receiving signal under tree cover (although the eTrex was slightly better than the Magellans). No idea if the more expensive models actually do, either, although some are touted as such.

MapGeneration Project

[Anonymous Coward]

Saw this one on freshmeat a few days ago:
http://mapgeneration.berlios.de/

Now all I need is a GPS receiver...

Re:MapGeneration Project

[Anonymous Coward]

This project is great, if you want to create a road map out of your data. The map is generated automatically without the need for manual editing.

Who's your Undeveloped country?

[Anonymous Coward]

I'm sorry, but the pc (political correct) term is "Developing Countries".

Re:Who's your Undeveloped country?

[Anonymous Coward]

No, that's not PC either. I think in Geography we were told to call them LEDs - Less Economically Developed countries.

Re:Who's your Undeveloped country?

[Anonymous Coward]

I prefer 'Pubescent Country,' personally.

Software tools

[wtanaka]

Power

There seem to be a lot of comments claiming you will need lots of batteries. I've found while travelling that two sets of rechargable batteries (whatever was in my camera and one fully charged spare) was always more than enough. I'm assuming the village you'll be in has electricity -- that's usually the first available utility in Chinese villages. You might consider picking up some kind of voltage regulator from a bigger city before you get there. They aren't that great, but they're better than nothing for electronics.

Software

I've used GRASS, while trying to construct a map of the touristy "ancient city" here in Xianggelila, Yunnan, China. It does reasonably well and, though it tends to crash a lot with large sets of data, it's ok for doing transformations on your data. The time consuming part (which I haven't done for my map yet as you can tell) is to take a bunch of points of interest and convert them into vectors for the left and right side of each road. That's a process that needs to be done manually and probably will involve a lot of fudging. I haven't found anything exactly suitable yet, so I might eventually end up using some vector drawing program to do that.

Accuracy

If you get a consumer grade GPS, it's not going to be that accurate. Probably around 10m. It's good enough to do larger scale maps, but if you're trying to map out a small village, you should probably take your readings all in the same day. That way, at least the points will be pretty accurate with respect to each other, even if they're all 10m east of where they should be. If you take readings on separate days, the changes in the atmosphere will give you different errors each day.

How I'd Do It

[taoboy]

Used a Garmin Etrex Vista to make outline maps of various islands in the Central Pacific atoll on which we lived. Worked fine.

The key activity in the field is data collection and retention. Get the points, store the points. Do the mapping later on better equipment. FWIW I'd want a unit with lots of memory to record tracks and waypoints, then a means to take rough bearings - with that, you can triangulate the positions of objects you can't reach. Then, the next most useful tool is a notebook that's comfortable to carry and write in. Forget PDAs for that task.

At the hut, have a laptop on which to download points and run your favorite mapping software. Light and rugged seem to be the top considerations; I'm typing this on a Thinkpad X30: 3.4 pounds, titanium alloy cover, $700 on ebay. That'd work. Also, get a couple of USB memory sticks for data backup; lighter than carrying a CDRW drive.

For download software, I just today downloaded EasyGPS; interfaces with a wide variety of units, and stores data in GPX (XML for GPS) format. Free. Their ExpertGPS product (not Free), looks promising too. Work out your software toolchain at home where you can download different tools, try 'em out. You don't want to be figuring out your tools in the field.

Biggest headache will be power. The guy who mentioned a solar charger had the right idea, for both AA batts for the GPS and the laptop. Saw a bicyclist's webpage not long ago describing his solar charging setup for his laptop; don't recall the link offhand.

Sounds like fun.

Re:How I'd Do It

[shintaro]

Pretty much how I'd do it too.

Use Garmin 60C
- Collect tracks
- Download tracks using Garmin Mapsource (provided with unit, Free Of Charge FOC)
- Trace or convert tracks to roads, outline, lakes, points of interest, etc using GPSMapEdit (FOC)
- Use cGPSmapper.exe (FOC) to convert to Garmin foramt
- Sendmap DOS version(FOC) send converted map to Garmin format.

Sweet.

How it be done

[Anonymous Coward]

Get a garmin, GPS3 thru 5 etc. You will need either a data cable to a laptop or a datalogger. This is because you can store more points/tracks on a hard drive. GPS units have small memory. You will need power for the units in the field, battery life is short, you can run both units of a car cigarette lighter. A good app. is Trackmaker and it is free, for the Mac try GPSY. ArcView is the GIS/GPS standard but is technical and complicated to set up logging, also expensive. You need a copilot to take down street names and play with the equipment. A GPS enabled camera might be handy to take georeferenced picts of signage. Study up on G.I.S. especially data tracks, points,
map projections, GPS, data storage and Integration. You may be able to burn your tracks to CD or upload them to the net nightly for storage via satellite internet if you have a fancy PDA SmartPhone. PCs are more the industry standard,
and lastly, Good Luck ;)

MOD PARENT UP

[identity0]

Geez, everyone here seems to be taking this as a joke or something, but here's someone who has some info.

That said, the submitter REALLY needed to be precise - What country? What type of mapping? What level of detail?

"West Africa" is HUGE, and there are varying politics, culture, infrastructure and religion in each country. If you'd asked about "East Asia" South Korea is so developed that you could buy any kind of map you need, but next door in North Korea you'd get arrested for bringing in a GPS device. Details are important...

I have mapping experience

[terminal.dk]

making maps for orienteering. That is high-detail map, scale 1:10000 and 1:15000. And the best way to make maps is to draw them on top of aerial photos. You draw most of the map from home, and then go out in the terrain afterwards to fill in the blanks (tree/foliage covered areas etc).

Only use for a GPS is to adjust/correct perspective of the aerial photo. Most of the other stuff can be done to a reasonable accuracy using the brain, legs, and a compass.

LEARN and READ

[Craig Ringer]

Something I've seen missing from the discussion so far is much focus on understanding maps and navigation.

If you don't know how to read and use a map, it'll be much harder to make one that's even remotely useful. Get familiar with topographical maps, at bare minimum, and preferably other types you think might be appropriate. Study some cartography. Go out on a compass navigation training course - with not a single gadget on you.

I mean that about the training course, too. You'll learn much better that way, and learn things properly. Don't just think reading a book cuts it, you need to go out and get experience where you still have someone to pull you out or ask questions of.

Get the permission of the local authorities. Others have outlined why that's a very good idea.

I'd also suggest going on a few multi-day bushwalks before you leave. On at least one of them, preferably with someone experienced, leave your GPS unit at home. Why: (a) Bushwalking is fun, especially multi-day trips (b) it'll make you more confident in your ability to handle navigation and the work involved, and (c) you'll appreciate the practice.

Now, I've made some big assumptions about the sort of territory and environment you'll be working in. Even if you don't need the skills outlined above, though, they're darn good to have, darn fun to acquire, and it never hurts to be prepared.

I used to be a cartagrapher

[Mallaien]

I never used a GPS system but working for the government I helped them to digitize sections of the US, in the amount of 6 million sections. The software we used was Archview, its a great peice of GIS software. Just look up some stuff on GIS (Geographic information systems)http://www.gis.com/ to get a start. Im sure that some GPS hardware would integrate well with GIS software on a laptop. at least marking stuff on Lat and lon scales, road layouts can be inserted by hand, and some sattlite maps could help.

Re:I used to be a cartagrapher

[Anonymous Coward]

The software is actually called ArcView (now called ArcGIS) and it is made by ESRI. I don't know what your budget is, but the basic software is $1,500. I think you can get it half price if you can prove an academic affiliation.

I agree that it is a great piece of software, but in this case it may be overkill. If you simply want to make pretty maps then I would look elsewhere.

before gps

[Anonymous Coward]

why don't you try a laser inertial guidance system, it's what airliners used before gps, and when set correctly could give stupidly accurate readings, the only problem is that they are bloddy expensive
http://en.wikipedia.org/wiki/Inertial_navigation_s ystem
if you really want to get accurate, supplement this with a gps and you could potentially get readings down to inches but good luck finding this system unless you know of any huge aeroplanes being sold for spare parts.

Another major point

[McSnarf]

Get permission from the Govt. of Ghana first - trying to map places might be looked upon as espionnage and you might end up with a bullet hole in the cranium. Countries can be paranoid. Or they just don't like the idea of someone mapping their country for about 50 other reasons.

casual error vs bias

[mu22le]

More likely you'd have a 5-10 meter uncertainty, and you'd have a similar uncertainty with nearby landmarks (so if the village is next to the river, they're both uncertain by 10 meters but you can see where the river is.)

No. We are talking about a casual error, not a consistent shift in measurement (bias) (take a look at wikipedia Errors and residuals in statistics) If youmeasure the same locatio coordinates many times you will get many values, distribute around a mean value witha a spread of 100 meter. This means, btw, that the error on your distance btween the two villages will be sqrt(100^2+100^2)=141 meters

Re:casual error vs bias

[budgenator]

Maybe I missed something, but I thought the question was about making an map, some villages and roads kind of a thing, not a geodesic survey, and more likely not makeing a map but plotting some points on an existing map representing the present location of a village which will move around over long periods of time, and maybe some roads, two-tracks and trails which unless they are paved, deffinatly will move annualy and sometimes over-night with enough rain, or even dissapear; and the same holds true for rivers, creek and stream beds.
1. he should get a GPS and play with it a while, see how it works and how well before he hits the bush.
2. Get some books on land-navigation, Millitary or Civialian Orrienteering, and practice.
3. get a good compass, the US Army M2 compass is about as good as they get, better than the survey instruments used to survey in the 1800's.
4. learn to declinate the compass, magnetic north isn't geographic north and it does move, depending on where you are, magetnetic north can be 180 degrees from geographic north!
5. Get comfortable with the mill system 6400 mills = 2 pie radians, makes the math much easier.
6. learn to intersect and resect from know points
7. learn dead-reconning as a sanity check on everthing.
8. get GMT, Generic mapping tool, GMT it's about as good as it getts too, GPL runs on about everything.

always remember a stardard wood pencil lead can be 100m wide on a 1:50,000 map!

Accuracy

[prabha]

GPS Gadgets will have accuracy in the range of 10 to 100mts, depending on the location,constructions or destructions around you. In USA some of the models comes with WAAS (Wide area augmentation system), WAAS is a differential GPS system which uses directional satellites (INMARSAT54A) focused inside USA. This means outside USA, WAAS will not be funtional. you can always use the normal GPS functionality without WAAS(this gives uptill 10mts resolution). Most of the GPS systems comes with user defined mapping systems, if you are serious about mapping villages,etc i suggest you to hookup a laptop which can do the detailed mapping by using the GPS attached to UART/USB/Bluetooth,etc.

Freely available map data

[Anonymous Coward]

The http://www.openstreetmap.org/ project is
working on making
freely available map data for the entire world.
It might be a good project to visit to learn more
on the available tools and data sets available.
There are elevation data available from 60
degrees south to 60 degrees north and good
satellite images available from NASA.

Navio GPS

[Anonymous Coward]

I find Navio GPS is pretty useful - http://www.tinystocks.com/gps.html - you can scan in a map, calibrate it, and it will move to follow your own position when the GPS is attached, plus all the usual waypoint features.

Apparently some people in Mozambique are using it to map malaria incidence.

Here's what I use for my Mac

[Richard Fairhurst]

• Garmin eTrex. Dirt cheap consumer GPS, pretty rugged, 'smart' tracklog recording and good battery life. There are plenty of accessories available for it: 12v adaptors, bike mounts, RS232 cables, etc.
  If I were buying new, I'd probably go for a Garmin Geko, which is similar but has larger tracklog storage capacity.
• A Keyspan RS232 to USB converter (USA-19 model, but they're probably all the same).
• GPSbabel or MacSimpleGPS for downloading tracks.
• A homebrew Perl script to take the resulting GPX tracks, and draw an Adobe Illustrator 6 file from them.
• Adobe Illustrator. Earlier versions have 'teh snappy' and can be picked up for a few quid, but require Classic. Newer ones suffer from feature bloat and cost loads, but run natively under OS X.

Will your results be compatible with Google?

[MarsGov]

If you're producing this data, I strongly suggest that you make the data useful. Will you be able to feed it into Google Maps, or Yahoos's mapping service, or others?

I suggest you find out from Google Maps how to create data that's compatible with their systems. In fact, maybe they (or a competitor) are willing to help sponsor your trip, if you can explain how your maps will help the Africans.

I've done this

[Anonymous Coward]

I am currently working in the Peace Corps in North Africa, and I am doing exactly the same thing, with a Mac.

I have an el-cheap-o GPS unit which I use to acquire data points. I then enter these into an excel spreadsheet (manually, cheap GPS has no interface).

I then used my favorite vector drawing application (in my case illustrator) and studied the coordinate system a bit. After figuring I could make a 15,000 by 15,000 "point" document, I was then able to decide that 5,000 points would equal 1 degree of longitude or latitude, thus laying out a mapping area that covered a 3 degree 3 degree grid.

Then I wrote a quick function (easy) with excel to convert my data points into illustrator's coordinate system. Then I just assigned points ( and graphics, say a well or spring graphic to represent such places) to the coordinates created from the data points.

There are probably better ways, but operating on a Mac you don't have a lot in terms of mapping software available, and working in something like Illustrator gives you a lot of creative control and the ability to map a lot of points, organize them into layers, and to then show only the information you're interested in (Such as water sources and roads, or water sources, roads, and schools to present the availability of water for school latrines/hygiene.)

I would be happy to send over example files. Contact me through my website:
http://www.meinereisen.org/

Workable set-up

[Anonymous Coward]

I'm doing the same thing mapping archeological sites and sites of interest in the mountains of rural Japan. Get a PDA with bluetooth and a bluetooth GPS. You can buy or easily build a battery pack to recharge them when you're away from the grid, you can keep them running in your pocket or bag so no one thinks you're doing anything strange, and if you can get any kind of maps at all to use as a base, you can use http://www.pathaway.com/products.htm Pathaway as your GPS software--it lets you roughly calibrate the maps before you leave on your PC, then calibrate them precisely once in the field and then you can also mark points on the map--it'll store a memo of what you marked, its precise position, and its position on the map. When you do take the PDA out to mark something on the map or write a memo, it's small enough not to be conspicuous. A lot of stuff on the map will likely be way off but that's why you're out there getting better data. Finally, in relatively open areas free of skyscraper canyons in the latitudes of West Africa, you should get great satellite coverage. Finally, you can get small protective cases for the PDA--put that in a ziplock and it's waterproof, too. The GPS unit itself should be small rugged and well-sealed. Finally, the GPS unit can stay well hidden and the PDA is much smaller than any standalone GPS, so it makes a less conspicuous, more easily carried package. I leave mine running in its case and makes a nice precise track of everywhere I go. I suppose if I didn't want to pull it out to mark something, I could just walk in a big circle, and then when I reviewed my track later I could put the mark where the big circle is. For something like what you're doing I'd also get one of those http://www.vosonic.co.uk/vp3310.html card reader/mini-HD things for backup so I'd be sure not to lose all my work if something happened to the PDA or card.

NO encryption! NO passwords!

[Nikolaj]

If you are going somewhere where armed militias - governmental, tribal, rebels, whatever - might be present, you do NOT use encryption on your hardware and you do NOT use passwords!!! Whatever OS that is on your device let it log in automatically. And you should use Windows so some outback militia who decides to take a look at your data has the chance to search through all your data as fast and seamless as possible.

If they think you have the slightest thing to hide, you might disappear in a jail - or end up dead.

(An advice I got from a field doctor from Medicins sans Frontiers).

To avoid trouble I also suggest that you get authorisation from any local authority before pulling out your GPS system in public. That stuff is very dangerous voodoo.

Yes, ASTER L1B is free + High resolution satellite

[Lord Satri]

You can bypass the 60$US handling for ASTER L1Bdata by using the link provided in my first comment.

Meanwhile, I only suggested Landsat-7, ASTER and SRTM-DEM because they're free, but there is of course many other sources of satellite imagery (see me previous comment on the thread for the link). The problem with 62 cm Quickbird or 1 m Ikonos, it's the cost of 22 and 7 $US / km2 with minimal purchase of 25 and 49 km2.

Call the professionals

[Anonymous Coward]

Well, there's these guys I work with that are good at making maps, they call themselves "Surveyors" and they think that GPS units are nice toys that can tell them approximately where they are. They seem to think that 10m accuracy is pretty mediocre and that they should be better than a centimetre. I certainly care when the building columns that they set out are not in the correct places.

Their tools haven't changed much in more than a century except they now use really expensive GPS/GLONASS systems for approximating or getting relative positions. Apparantly these guys, using a theodolite and compass can make a reasonable guess on where something is.

MapAid

[minialed]

Can I take this opportunity to plug MapAid who provide mapping and geomatics experts to humanitarian and disaster zones worldwide, including Western Africa. Geographic Information and expertise is a hugely valuable form of aid in all kinds of ways. The utility of GI in this kind of area was shown best in the recent tsunami disaster where the response from GI providers and professionals was massively useful in the immediate aftermath as wll as long-term recovery efforts. Aled

Re:NO!! (ok, just Nope)

[tfmkayaker]

The compasses in GPS receivers are mag flux valves - you "calibrate" them to local conditions via a procedure... you kick it into compass cal mode, and then rotate the unit slowly, in a level orientation, for 2 full turns. The unit can then compensate for some local effects.

Garmin is the way to go.

[J. Charles Holt]

As far as equipment goes, buy a Garmin. They are practically indestructible, extremely user-friendly, inexpensive and feature heavy. The 60C will run for over 20 hours on two AA batteries, and that's WITH a color screen. People in the military regularly have family members buy them Garmin GPS and ship them over to where they're deployed. That ought to say something for their quality level. Being that you'll be in Africa, it should work great for you. Where GPS can have problems is in canyons, dense tree cover, or in a city like London with very tall buildings (which can deflect the signals and cause the GPS to get very confused). Sadly, none of the Garmin mapping software works with the Mac. This doesn't sound like it should be an issue, since you won't be downloading maps of West Africa into the unit anyway. :) There are also third-party options available which will give you other capabilities. Good luck on your trip, and make a difference out there.

Read the fist eight words again!

[Anonymous Coward]

"My girlfriend lives and works in West Africa..."

Hear that...GIRLfriend. Know what that is?

Compass Use

[DG]

One of my major tasks, back in my Armoured Recce days, was to always know exactly where I was (to a resolution of 100m) without the aid of a GPS, while commanding a group of moving vehicles.

To do this, one must hone one's spacial recogition skills to a particularly fine pitch. I got to the point where I could see contour lines on a map, and visualize the terrain so represented from the POV of an observer on the ground.

Through a combination of mental dead reckoning, spacial awareness, and map reading skills, I could usually keep track of where I was at any given moment as a kind of mental background task:

"I'm here, moving a little west of north at 30 Kmh, so I should be crossing this stream in about a minute, where I'll be be able to see this hill here and there's a cemetary on the left another 600m up the road and the road bends a little left another 300m up from that and then I'll see this woodline here and....."

But to pull that off, you need an accurate map and sightlines to all the features you use to orient yourself. If either of these is lacking, a plain old ordinary mil-spec Silva Compass can be a real lifesaver.

I was on a trace once in Gagetown when a thick fog settled in, limiting visibility to about 300m. Somehow, I got turned around in the fog, and the references I kept expecting to encounter weren't there. I dragged out the compass, and it indicated that I was moving 90 degrees off from the direction I thought I was (the fog was diffusing the sunlight to the point where I couldn't even use *that* as a reference)

This was a profoundly disorienting experience. I *knew* North was that way ^ but the compass said it was this way . I actually thought that the metal hull of the track was confusing the compass, and I had to dismount and walk a couple of hundred metres away from it before I was finally convinced that *I* was wrong and the *compass* was right.

With the "which way is North?" question sorted out, I was able to re-establish my actual position in relatively short order, and resume the trace.

I would recommend that the OP spend a good deal of time doing map and compass work, learn how to do that, learn how to annotate a map, and once those skills are honed, THEN get the GPS. The combination should ensure the best possible chance of success, and doesn't place his life in danger if his batteries die.

Another tip - laminate all your maps with maptack (it's a sticky clear film availible at map supply houses) on BOTH SIDES of the map, and use Staedtler "Permanent" markers to annotate it (the markers will clean off with alcohol, but will not run in the rain).

PS - Hey Kevin, long time no see. :)

DG

Software Answer

[Illix]

I'm surprised no one mentioned this (or if they did, I didn't catch it) but if you're getting a GPS and worrying about power already, you may as well shell out the cash for Google Earth Plus ($20) or Google Earth Pro ($400 with a 7-day free trial).

Besides the fact that they're awesome, these programs have satellite maps of pretty much everywhere, so if the villages have been in the same place for the last few years they're almost certainly in the photos if not technically "mapped." Plus, I've discovered that Google Earth is a spectacular ice-breaker; showing people pictures of the Grand Canyon or Mount Etna or even their own house is almost always enjoyable, and photos translate into any language.

GF?

[Anonymous Coward]

You have a girlfriend? w0W! You should chart that territory!

Maps!

[sciop101]

Get topographic maps of the country, either CD/DVD or paper.

WARNING! Some countries consider topographic maps as sensitive military information.

GPS will show errors/changes in old maps. Uncharted villages maybe nomadic. Rivers change course, lakes dry, and villages move. That's life!

UK Mapping was Re:Hello?

[ianturton]

The OS was very acurate, I imagine they would have been upset at only a metre accuracy.* However it is dificult to match GPS up with OS basemaps as a result of projections changing. Originally OS base mapping was on a county by county projection, which meant that the edges of two counties didn't line up very well. As the OS moved to a national projection rather than completely resurvey they reprojected the old maps to the new base. This persists in places near the edge of counties and has only become a problem when people started to expect thier GPS track to actually land on a road.

They've pretty much resurveyed all the important bits of the country (i.e. where people live) and so this problem occurs most in rural areas.

Ian

*It was the accuracy of British Surveyers in India that lead to the discovery of the geoid. This beacuse as their survey approached the Himalyas the plumb bob of the theodolyts was pulled off vertical leading to a differnce of a few feet in the length of India as measured by triangluation compared to the direct measurement.

What we use

[fotang]

The GIS unit in the Cameroon (in West Africa, for the geography-challenged) office of an international development organisation that I work for. We use the following to map out villages (water supplies etc):

• GPS receivers: Garmin eTrex summit (has in-built altimeter!); Garmin GPS 76; and Garmin eTrex personal.
• Software: MapSource (we get the CD with each batch of receivers that we buy from Garmin); ArcView (or, as of now, ArcGIS -- if you can afford it).
• Altimeter: pocket altimeters from Thommen.

The Garmin GPS 76 is currently my favourite; large screen and easy to use-- unfortunately it has no altimeter (I hear it uses triangulation or some such to get altitude).There're lots of other things but they're not strictly necessary at the beginning.

I have never been able to get GRASS to compile on Linux, so all the software above is for Windows.

/fotang

Don't forget about datum and map projections

[Anonymous Coward]

It has been a while so you will need to do some reading but remember that GPS uses WGS84 which could be very different to what they use in the country you are going to.

If you can find a local map there is a good chance it won't be in nice UTM projection so you will need a way to take lat lon in WGS84 and transform the datum and project the points into xy coordinates that you can plot on the exisiting map.

Never speak of undeveloped countries

[rtssmkn]

as they are only undeveloped the the concern our considering as how their economy and industry has developed in respect to ours over the last fifty years. Never regard them as customers of your choice as that will lead them to total destruction of a) their culture and b) their land and c) their inhabitants. Why? Now, we have overcome the times of colonialization, and you Americans should see to it that you do not do the same mistakes that the Europeans have long ago, we should seek to overcome the requirement to develop undeveloped countries to our likings. Second, They are a prosperiting culture that even developed an antigen for HIV by human intervention and invention alone, ie the human body developed an HIV antigen that is absolutely safe and sure to get rid of the HIV. Yet, patenting systems around the world especially regarding the pharmaceutic industries prevents them from developing the antigen to produce the required drugs. So why cartograph the land? A land that is burned so to say, with the Europeans first colonizing the land and destroying the cultures of the people that lived in these lands and economies now that harvest the land and drive the people into poverty and the opposite of what we call prosperity. I say, do not. They have to explore their environments as we did, we should not bother nor take any care nor show any charity to them as they are a proud people and deserve to develop themselves as we did and as they did long ago, even if that means genocide and all of which that comes along with that. And this is just the way that the Starfleet Command seeks out new land to discover in places where no man (no today-American) did go before. Let it be that way, I say. Just my two cents, Carsten

An organization that does this...

[eSage]

You might want to check out Mark Plotkin's site and/or contact his organization via http://www.amazonteam.org./ His NGO not only maps indigenous lands in the Amazon to protect them and the tribes' ways of life, but he also teaches the tribes to use GPS mapping equipment so they can help their neighbors. I'm sure they would be glad to direct you to the resources you seek. Good luck!

Other more important things / tried & true met

[Cedric Tsui]

I believe for GPS to work correctly, you also need a very accurate clock, which is broadcasted from ground stations. So your accuracy may be determined by the quality of the local ground station. This is probably more of a threat to your GPS system than some US signal weakening. (Not even sure how the US can selectively desensitize certain countries, other than little metal shields in front on the satellite anteni in the shape of evil country x)

If you need a very very accurate map (which you probably don't) it would be best to stick to tried and true methods. You make a concrete secured post and define it as the origin for you axes, and you use laser ranging with ground surveying. (in case anyone doesn't know, you've got the tripod with a self leveling, north aligning telescope, and a height bar with a bubble level, 2 people can map a whole region pretty easily)

Then you can simply improve the measurement for your origin with the GPS system as you require (and as technology will allow)

But I'm guessing you don't need anything this accurate.

In that case, purchase a satellite photo of the villages in question. I believe they are about $500, but need to be ordered several months in advance. This will give you something solid to work on. From there, you can use GPS to measure distances from landmarks you can see on the photo.

Aside from this, make sure you do a long and hard literature search for any mapping work, (topographic, satellite, etc) you can get your hands on. Don't go re-inventing the wheel.

Oops.

[Cedric Tsui]

Oh, obviously, you wouldn't need to use the geological surveying methods if the GPS is accurate enough.

I'm not totally sure how you can discover if it is. The handsets don't report +/- values do they?

OziExplorer (PC) and Garmin 12XL

[Anonymous Coward]

I'd suggest getting something known to be reliable. Garmin 12, or 12XL are good units.

I'd suggest the 12XL as it has a built in voltage regulator and can take anywhere from (check specs, this is from memory) 8 to 36 volts DC and convert it to what it needs. (The 12 required a regulator in the power adapter, not good if you have to wire it up in the field).

Take some spare batteries with you. I would recommended a case of Lithiums. They are only for use in emergencies and they weight less than Alkaline. They also work better in a wider range of temperatures. (They work when it's -30C, where Alkaline will die in about 10-20% of the normal time.). I realize Africa isn't known for it's cold weather, but you want reliability in the field, and who knows, it could be in the negatives at night.

OziExplorer is good software, you supply scanned images of base maps (you may be able to buy some for the area you will be in, otherwise you can scan your own (in which case you have to calibrate them).).

Keep a log book of vilage co-ordinates. Computers fail. Hard drives die, memories get erased.

Something like the 12XL will store 500 Waypoints, this means you could easily track 2-300 vilages with enough waypoints left over to track stuff your interested in on a daily basis. If you use a laptop you can offload the tracks from the days travels and use that to build a roadmap of areas traveled.

(OziExplorer (or similar software) supports upload/download of waypoints and tracks from/to the units. Keep in mind older GPS units require serial ports, while newer ones may be USB. (And no, USB to serial adapters do not always work with GPS units.).

-- topham@shaw.ca

Low Tech?

[evilbessie]

Well it's nice to know all the posts seem to be championing the benifits of this modern technology. However the first maps of Great Britain by Ordinance Survey were published in the C18. The first map of the whole country using the method explained here http://en.wikipedia.org/wiki/Ordinance_Survey had an error of some 46 cm between the main two baselines. This method must have some merit.

You'd Be Amazed Who Sells Batteries

[cmholm]

You think just because someone is at the ass end of the supply train, no got batteries? During my Scout troops' 50 miler in backcountry Iran, I found that if a village stand was selling anything other than vegetables and dung "fuel discs", there'd be a few 9v and AA batteries in stock... which fueled my Dooble Bros jones.

Re:Other more important things / tried & true

[topham]

GPS does not require a highly accurate independent clock.

If you want accuracy down to the centimeter level there are some steps you would need to take. But mapping the location of a village on a map doesn't even require the level of accuracy you will get with a GPS received. Any GPS receiver.

While GPS does require a highly accurate clock, it is basicly self-calibrating. You simply turn on a GPS Receiver and wait a reasonable period of time and it will set the internal clock itself, it will download the satellite data so the next time it starts it will lock on faster, etc. A GPS unit bought new today typical can receive 12, or more satellites at once, will configure itself at it's new location in under 10 minutes. (It may take considerably longer than normal start times if a GPS unit has traveled a great distance, and has out of date ephemeris data, but it will sync up on it's own. (Older units sometimes needed to be nudged, you would have to get them an approximation of their starting co-ordinates, didn't have to be right, just approximate).

(This data will be automatically downloaded by the GPS when it is active, but may take several hours to collect all the data. Not really a big concern since it will collect it on an ongoing basis.)

Software to avoid

[the real darkskye]

Having had some experience with GIS before I will give this advice:

Avoid ESRI software.
Its slow and bloated (in my professional experience) and there are much smaller and better GISes out there, such as MapInfo.

Compared to ESRI and some in-house systems, MapInfo was much neater, smaller and faster to use.

Geoid

[Anonymous Coward]

The GPS may work, but maps will not, unless you use US maps. Most countries use their own geoid, so the location will appear to differ. You need to set your GPS to their geoid/system.

Re:Other more important things / tried & true

[Kadin2048]

Actually, GPS does require a very accurate clock. Several of them, in fact. Luckily, they put them way up in the sky, on satellites. This is how the system works: the GPS satellites are constantly transmitting a signal which contains (among other things) their ID code and the time. The receiver uses these time signals to figure out how far away the satellites are, and from there discover its position. (This is a gross oversimplification, but you get the idea.) An atomic clock is NOT required in the receiver, or on the ground at all.

For a less gross oversimplification: :-)
http://www.nasm.si.edu/exhibitions/gps/work.html