There can be only one img-file on this card in this model (must be called "gmapsupp.img"and placed into a folder called "Garmin").
However, this img-file CAN consist of more maps (a mapset) created by MapSource and downloaded to the SD-card.
That means, that you must have all wanted maps installed and unlocked in PC and for this unit, within MapSource, in order to create this mapset.
Mapsource with all the maps installed is the easiest and most flexable way to get all the maps you want into a single gmapsupp.img but if you have only .img files you can simply join them all together using the gmaptool.exe and the results are identical. That goes for all model Nuvis, not just the 7xx series.
The Oregon and the Dakota and the Colorado are different from the Nuvis in this area.
You can give the maps any name you want as long as it ends with .img.
I have ~10 different maps on my Oregon. e.g.: Europe.img, Germany topo.img, Swiss topo.img etc etc.
You only have to make sure that the amount of all maptiles (interior and sd-memory together) does not exceed 3500.
allo i like to have info how to install masp
Garmin City Navigator North America 2011 10 (Unlocked) 1.23 GB
on sd card 2 gb do make format fat32 for the sd card,,,,
Very simple on a 750:
1. Right click the SD card from windows and format the card if you feel it is necessary (either FAT or FAT32) will work with a 2G card.
2. Right click the SD card from windows create a new folder on the card and then rename it 'garmin'. Your 750 will only find maps if they are in the 'garmin' folder of an SD card.
3. Now just copy the large 1.23 GB (UNLOCKED) 'gmapsupp.img' file to the 'garmin' folder of the SD card. If that large img file you have is named 'gmapprom.imng' you will need to rename it to be 'gmapsupp.img' in the SD card or your 750 will not recognize it as a map file.
4. you are done.
Reboot the 750 and your maps will now show up on on your 750 'map info' screen with a check box where they can be selected/deselected for use.