Is it possible to change the basemap of a Garmin mapping GPS unit?
A. No. For example, if you purchase a unit that comes with the Americas Autoroute Basemap, you will not be able to download and program the unit with the Atlantic Autoroute Basemap. You may download additional mapping detail to many of our GPS units–if they have additional memory for map storage–by using one of the compatible MapSource mapping programs. If you want to know which MapSource products are compatible with a particular GPS unit, visit that product’s web page and look in the upper right-hand corner of the page for the “MapSource Compatibility” tool. This will allow you to view the various compatible MapSource products that may provide the detail you are looking for.