Originally Posted by Yossarian™
The phones typically get a location fix from the on-board GPS chip, but putting maps on the screen depends upon a connection to the cell system data, in order to download the maps from Google. No cell connection, no map. Airplane mode would cause the same problem.
Of course, if this app has the map data already loaded, then no issue.
I writing the app, so I can make it do anything I want really. It will have a feature that will allow you to request it to prefetch map tiles from around tracks of you select. Not all the tiles come from Google either. The Topo maps are USGS scans from ESRI. The app currently renders OSM vector files which are available for nearly the entire planet so offline maps will not be a problem at all. The limitation for offline map tiles will be the storage capacity of your phone, but for a narrow band of a couple hundred miles I think the storage will be adequate. I can always put another sdcard slot in the remote control for more offline storage as well if that seems like its needed.