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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?"
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.
What I'm listening to now on Pandora...
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.
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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.
Rosco: "If brains were gunpowder, Enos couldn't blow his nose."
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.
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.
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?"
There are 10 kinds of people in the world - those who understand binary and those who don't
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.
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Solar battery chargers:
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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.
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.
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
l'Homme n'est Rien l'Oeuvre Tout: Gustave Flaubert to George Sand