Un llibre interessant sobre la informaciķ geogrāfica voluntāria <a href="http://www.springer.com/earth+sciences+and+geography/geographical+information+systems/book/978-94-007-4586-5">http://www.springer.com/earth+sciences+and+geography/geographical+information+systems/book/978-94-007-4586-5</a><br>
<br>Raf<br>