I got to say that that idea was actually pretty good. gnuite: do you think it might be possible for you to add a 'own image' support. The calibration would need the user to view 'own image' over the satellite/map image. On the side of the screen would be rotate right, left buttons and scale up/down buttons. (or sliders for those) scaling would be done within the chosen resolution. Or other way would be to ask user to make a triangle on both maps by clicking on the same landmarks and the system would then calculate the needed rotations and scalings.

Map would of course be then split to subfiles as is the way done in the current maemo mapper.

Also, supporting overlay color would be great (click on a pixel on own map to make that color transparent.