It would really be great if gpsapp could use the gdf format, because you can buy a CD of your region.

Yeah. Someone please remind me...

What's stopping us from taking an existing map CD in a proprietary format (something you'd pay money for and purchase) and then reverse-engineering its format for use with the car player? Why does the data have to be in a "free" format? I know I'd pay good money to get better maps than MapsOnUs can provide.

Surely others have already reverse-engineered these map discs?