Merging Multiple Garmin Image Map Sets

Saving different maps into different mapset files also allows you to easily replace the map to newer versions in the future. However, if you have a lot of maps that you want to load into your GPS, or you want to store all the maps into a SD card which supports only a single gmapsupp.img, you might need to combine (join) the maps into one mapset file. GMapTool is a tool which allows you to join and/or split maps into mapset files.

Download GMapTool (mirror). It supports multiple platforms:

• Windows – GUI and command line
• Linux – command line
• Mac OS X – command line

Using the GUI interface of GMapTool makes it pretty simple to combine the mapsets.

Firstly, store all the mapset files you wish to combine as different filenames on your PC. It is recommended to store them in the same folder/directory.

Under the Files section of GMapTool, select the maps you want to combine by clicking on Add Files (to select one file at one time) or Add Directories (to select all *.img files in the directory). Note that you can always remove any file in the listing by selecting it and press the Delete button of your keyboard.

When you are done with the mapset selection, continue to the Join section.

Specify the Output File, and key-in the Mapset name of your file to be created. This mapset name will be displayed under each of the map name when you list your maps in Map Info function of your Garmin GPS.

Click the Join all button, and the combined mapset will be created. You can then copy the new mapset file to your Garmin’s internal storage or SD card.

Note that if any of the maps in your mapset file are locked by vendor, you still need the 25 bytes unlock key stored in a *.unl file in the same folder and with the same name as the mapset file where the locked map is stored in. To unlock 2 maps inside the mapset file, put both the keys inside the *.unl file one after another, without space (the file size will be 50 bytes then). To avoid this hassle, you might want to use Garmin Unlocker to permanently unlock the maps before combining them with GMapTool.