I've found a new, hobby, one that is possibly int he ultimate geek league - OpenStreetMapping. This is an attempt to create a freely available, freely editable source of map data to all, in the same way Opensource software works (free as in beer).
There are several ways people can contribute, there's an online map editor, a downloadable java based client for editing, and a system to upload GPS tracks of areas, Yahoo have also geenrously allowed the project to use it's aerial photography to generate maps from.
You can see my tracks here and my userpage on the wiki here.
Why ? From the wiki:
Geographical data (geo data) is not free in many parts of the world, like the United Kingdom. Generally these places have given the task of mapping to various government agencies who in return get to make money by selling the data back to you and me. If you live in one of these countries, then your taxes pay for the mapping and then you have to pay again to get a copy of it. In the USA crude data (such as TIGER) from the government, is in the public domain, however refined data and finished maps are generally commercially copyrighted.
Data from commercial mapping agencies contains lies, or Copyright Easter Eggs, to catch out anyone copying it. These easter eggs take the form of fake or missing streets, or features like churches and schools that don't in fact exist. If you make a map using their data, they can say "ah-ha! Gotcha!" from looking if you also copied these fake pieces of map. The map may also just be incorrect because for example you bought it a year ago and a path has been dug up in your local park since, or someone just made a mistake.
If you accept all of this then you still can't do anything with the data but photocopy it. In lots of places thats illegal too if you go beyond your fair use rights. You can't correct a street name, or add the pub/bar over the road, or use the data in a computer program without paying a lot of money. More money than you probably have. What about sending it to a friend, enclosing it in an invitation or posting it on a notice board? A lot of these are less legal than you might think.
Advances in technology like cheap GPS units mean you can now create your own maps, in collaboration with others and have none of the restrictions outlined above. The ability to do so allows you to regain a little bit of the community you live in—if you can't map it you can't describe it.
