BaseCamp reads the same maps as MapSource assuming it's not marine BlueChart maps. Originally the first release of BaseCamp was only detecting maps with DEM layers. Now that extends to pretty much all installed MapSource maps.
The format can be a Garmin FAMILY directory (eg. C:\Garmin\FAM_xxxx) with a lot of img-files for the map tiles or as a newer GMAP directory. The GMAP style is also compatible with Mac.
Another possibility is to read maps on memory cards. BaseCamp scans attached USB sticks and memory card readers as well as attached GPS units in USB mass storage mode.
Thanks i understand and i can see now a method of some trial runs , i like all this gps stuff, its very impressive and the map display in basecamp is like you 've got the old map spread out wrinkled on the desk and looking it over.I use the 760 in a vehicle and the 60 csx handheld both good units
Thanks for the info ---so i have gmap3d.img and gmaptz.img ,with basecamp running and updated how do i get these maps in place
gmap3d is the file that contains 3d buildings that can be used on some of the Nuvi series (7x5, 37x0). AFAIK, there is no way to view these on the computer, only on a compatible GPS unit.
gmaptz is the timezone file that allows the Nuvi to know when you have moved into a different zone. Again, it doesn't work on the computer, only on a GPS.