There's plenty of apps on Android that use downloaded maps. http://wiki.openstreetmap.org/wiki/Android http://wiki.openstreetmap.org/wiki/Android Unfortunatel

There's plenty of apps on Android that use downloaded maps. http://wiki.openstreetmap.org/wiki/Android http://wiki.openstreetmap.org/wiki/Android Unfortunately AFAIK most of them are missing many of the things that makes Google maps useful. Real time traffic data, real time road closure data, updated public transportation schedules and closures, search by something other than address, ... Also I believe online vector based maps teams found that vector map data was actually larger than tiled map data. I thought as you did lines = smaller but lines + colors + line weights + building outlines + elevation contours + street names + road direction info etc adds up were as jpeg tiles can be pretty lossy.