Diappearing Garmin TOPO U.S. 24K North Central

The additional TOPO map will be stored on the microSD card, there will be a single file called /GARMIN/GMAPPSUPP.IMG, this file can contain multiple maps, but you can't have more than one file and you can't change its name. It is possible to copy and paste to your GPS but the file must be in the correct format and it must be called GMAPPSUPP.IMG, if you copy and paste a new GMAPPSUPP.IMG file to your GPS it will replace any existing file of the same name and you will lose the maps contained in the original GMAPPSUPP.IMG.

You can add a new map without losing any existing maps by using a computer program like Garmin Basecamp, this can copy the existing map and add it to a new map, downloading these two maps to your GPS will create a new GMAPPSUPP.IMG file containing both new and old maps

 

Ah O.K., so the question is where are the map files installed onto the computer, got it, once the files are on the computer an install onto microSD would not need the DVD disk to be present, because the copy would be from the hard disk rather than the DVD. In order to to view the maps on your computer (or to copy to microSD), you would need a program installed on your computer that can use the map files, i.e. Garmin Basecamp as mentioned above, As long as Basecamp can 'see' the files, their location is not really important because the files are re-packaged by Basecamp before transfer, the files can be in various formats, e.g. *.img etc. so that is what you would have to search for, possibly in locations such as :-
C:/Garmin/maps/topo/filename.img