well if its for learning about earth and stuff, perharps there could be some way for people to add some feedback... people can tell about history and good touristic points... and add their coordinates...
say.. in a wiki like site...and if you're going to france you could download the file on france, with coordinates, tips and use the map to travel and stuff?
Perharps people would like to do some previous research and create such file based on wiki or other and snap it on you app, save the maps and stuff of the place and use it as a guide? and share it later?
