Tomasz Wegrzanowski wrote:
Once we have the data, the software itself isn't that difficult.
Actually, you can do a lot of fun with geo coordinates even if you don't have access to mapping data. For example, you can compute the distance between two coordinates or you can list coordinates that are within close range of each other. In an article on Napoleon, you can follow every [[link]] and see if the pointed-to page has a coordinate, then you can put all these coordinates as numbered circles on a map overlay, to trace Napoleon's world tour. Then add this overlay to a map if you have one.
Just like ISBN: numbers can be useful with any different online bookshop or even without any online bookshop, GEO: coordinates can be useful with different online map sources. This could be selected with individual user preferences. If I am a subscriber to a commercial online map source, my personalized view of Wikipedia could render GEO: coordinates as a link to that source. Since the contents with the GEO: coordinates is distributed under GFDL, another website can do something else with the GEO: coordinates.
On http://susning.nu/Wroclaw the wiki text map:51.11:17.03:100000 (i.e. geo 51.11 N, 17.03 E) is rendered as a link to http://www.mapquest.com/maps/map.adp?latlongtype=decimal&latitude=51.11&...
The difficult thing is to agree on the exact shape of the world (ellipsoid, geoid). Converting between Greenwich and Paris meridian, between decimal and non-decimal degrees, or between different projections is trivial. But is 51.11 and 17.03 the official center of Wroclaw? Or is it a few dozen meters off? Mapquest seems to draw this coordinate at the Ratusz (town hall), which seems like a good choice, but another map source might have a different opinion. What does your GPS tell you? And which coordinate should be in the Wikipedia page? This is where some knowledge about cartography could be very useful. See http://en.wikipedia.org/wiki/Map_projection#Choosing_a_model_for_the_shape_o...