Mapsource tutorial: How To Install GMAP Folder To Mapsource
Method 1:
this example uses "City Navigator North America NT 2011.31.gmap" folder
Windows XP:
Copy "City Navigator North America NT 2011.31.gmap" folder into
%ALLUSERSPROFILE%\Application Data\GARMIN\Maps
OR
%APPDATA%\GARMIN\Maps
Vista, windows 7 and and above:
Copy "City Navigator North America NT 2011.31.gmap" folder into
%ALLUSERSPROFILE%\GARMIN\Maps
OR
%APPDATA%\GARMIN\Maps
(e.g. C:\ProgramData\GARMIN\Maps or something like that all other languages)
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