Online Collaboration Creates 'Map-Making For the Masses'

The Science Daily site has up a piece on the effect user-generated content can have on map-making. Scientists are appreciative of the data enthusiastic mappers can provide, updating maps on changes in local geographic information. "Goodchild's paper looks at volunteered geographic information as a special case of the more general Web phenomenon of user-generated content. It covers what motivates large numbers of individuals (often with little formal qualifications) to take part, what technology allows them to do so, how accurate the results are and what volunteered geographic information can add to more conventional sources of such information."

Comments

OpenStreetMap

[saibot834]

In TFA, they are refering to OpenStreetMap, a wiki-style project to create free street maps. (though this is not mentioned in the summary)

Nice maps from Openstreetmap

[emj]

They have come a long way:
Birmingham
London
Stockholm
Falköping

There aren't that many people maping (1000?), and you can really make a great differance by just adding all pathways you use for your daily strolls..

Re:Nice maps from Openstreetmap

[protolith]

You ran into the fundamental weakness in most GPS Systems. The x and y are relatively easy to get. the z is always less accurate.

I used to use a Trimble TDC1 ($12,000 near survey grade GPS) with Realtime differential correction.
With 20 points collected on a position and post processing, the x and y were good to about 10 cm yet the Z was usually only good to roughly the nearest meter.

In order to get better results. The GPS antenna needed a large plate attached to act as a shield to block the radio waves from reflecting off the ground and interfering with the data collection, data collection must be more intense. We would usually collect between 1000 and 2000 points With realtime differential correction. after post processing the x and y would be good to the millimeter, yet z was then good to around the cm.

This was roughly 6-8 years ago, now with selective accuracy turned off, it is easier for lower end units to perform in the sub 10 m accuracy.

The quickest way to a decent topographic profile of a path is to record the path (as you did) and calculate the intersection of that path with as good a DEM (digital elevation model) as you can get a hold of.

Heres the actual paper

[jrcsnet]

This was presented at the Volunteer Geographic Information conference in Dec 2007, see http://www.ncgia.ucsb.edu/projects/vgi/.

The paper that TFA references can be found at http://www.ncgia.ucsb.edu/projects/vgi/docs/position/Goodchild_VGI2007.pdf

Another presentation on Openstreetmap from the same conference is at http://www.ncgia.ucsb.edu/projects/vgi/docs/present/Coast_openstreetmap-opendata.pdf

Using OSM on existing map sites.

[mcknut]

I've put together a little bookmarklet that lets you use OSM maps on Google maps and Multimap API implementations (and in fact multimap.com). In fact I updated it today and have a new blog post about it here.

It can be really useful when you find a site that has useful data but you want to see that data overlaid on OSM maps. On Multimap's site you can also see routes and lots of other POIs overlaid on the OSM maps too.

Two sites

[kbahey]

Two sites that are fine examples of collaborative creation of maps and adding info to maps are:

http://www.openstreetmap.org/
A from scratch volunteer effort to map the world using GPS, as people visit places.

http://wikimapia.org/
An overlay on Google Maps where people can mark their landmarks and comment on others.

Really really nice efforts.

The Confluence Project is used this way

[Terje Mathisen]

The Confluence Project http://confluence.org/ is an international effort to perform a systematic sampling of the Earth's surface, i.e. all those locations where both longitude and latitude has integer values.

So far more than 10,000 visitors have documented more than 5,000 of these points.

http://www.agu.org/pubs/crossref/2006/2006GL027768.shtml is a link to a paper by a Japanese researcher (Koki Iwao) and his associates: They have used the DCP information to check/verify the quality of the various land cover databases:

Which parts of the Earth is mountains/lakes/forests/rice fields/grassland/etc.?

What they found is that the best of these databases have a hit ratio of just 60% or less.

Terje
(Scandinavian DCP coordinator)