Looking at the code, it seems to be simply a program that takes a map image and selects a screenful depending on where the GPS says you are.

Edit: I suppose you could do the same thing on the empeg, though the resolution doesn't help. You really need a map-render as you want to show what's in front of you, not just a a section of the map around you. You'd have to limit it to a 32x32 square to get equal coverage.. If you render, you can do a 64x32 square of the road infront, with compas/location information on the right half..