Multiple maps on SD Card in 3790
I am new to GPS and just got a Nuvi 3790 a month back. Have been learning how to use it and this site is among the most useful and helpful.
Would like to share my experience with the Nuvi 3790. In the MicroSD card, under the /Map directory, multiple maps with any filename can be used simultaneouslySo long the file extension is .img (eg MapOfMyCountry.img), the device will recognise the maps.
Gmapsupp.img is recognized probably just in sd "Garmin" folder, just one in Garmin folder-
The only wrinkle is that for this to work, it depends on how the maps (files) are transferred to the MicroSD card :-
1) If the files are transferred by copying from a PC directly to the MicroSD card which is then inserted into the device, then the device must be shut down (ie not set to Sleep) and restarted. Do this by depressing the Power button for about 4 secs. The message "Turn Off the device?" appears . Tap on "Off" and the device shuts down. Start the device again by pressing the Power button. The devices power up and the text "GARMIN" appears and then goes through the start up process. After the device has restarted, go to Tools > Settings > myMaps. The newly copied files can be seen in the list. Check the maps you want enabled in the device.
2) The files can also be transferred with the MicroSD card inserted in the device and the device connected to the PC via the USB cable. In this instance, when the device is disconnected from the PC, the device will shut down automatically. Pressing the Power button will restart it and the new files can be seen as per the above.