Using JaVaWa GMTK To Fix Open Street Map Garmin Files

I am a big fan of Open Street Map (“OSM”) Garmin-compatible maps available from Whenever I travel, I download OSM maps of where I am going and install them on my GPS receiver.

There is one problem with OSM Garmin-compatible maps: you can only view one OSM map at a time in BaseCamp or on your device. This is because all OSM map files share the same map name and ID. (This is probably a result of how the maps are auto generated, especially ad hoc views which allow you to create a custom map by manually selecting tile segments.)

OSM Custom Map Built On Demand

OS - File Download

The excellent cross-platform JaVaWa GMTK (Garmin Map Toolkit) to the rescue. With JaVaWa GMTK you can perform a lot of map management tasks, including changing of map name and ID properties.

As you can see in the following screenshot, I have multiple OSM maps installed on my computer hard drive (I have renamed each of the .gmap files so I can have several in Garmin’s Maps directory). However, only the first listed OSM file would normally be available in MapManager, MapInstall, and BaseCamp.

Finder - Garmin Maps
Finder – Garmin Maps Folder
MapManager - Before
MapManager – Before

The process for changing a map’s name and ID is pretty straightforward. Make sure you quit BaseCamp/MapSource and MapManager first. I am doing this on a Mac, but it should be similar on Windows.

  1. Download and install JaVaWa GMTK.
    JaVaWa GMTK - Install
  2. Launch JaVaWa GMTK (on OS X 10.8 and later, right-click on the JaVaW MapConverter application icon the first time and choose the “Open” menu item — this will ask you if you want to bypass OS X’s developer signing restrictions — click the “Open” button).
  3. JaVaWa GMTK will scan your installed maps. (On OS X, map files used by BaseCamp are installed in the directory /Users/[username]/Library/Application Support/Garmin/Maps. Any problem maps will be highlighted in orange or red.
    JaVaWa GMTK - Before
  4. Click the map you want to edit and then click “Extras” in the toolbar and choose “Change map name and ID” from the drop down menu.
  5. In the dialog, set a unique Family ID (this must be unique across all your maps — GMTK will warn you if you enter a duplicate ID), and descriptive names to be displayed in BaseCamp and on your GPS receiver.
    JaVaWa GMTK - Modify
  6. Click the “Modify” button to save your changes.
    JaVaWa GMTK - After

That is it. Repeat steps 4 to 6 with the rest of your OSM maps. Quit JaVaWa GMTK and launch MapManager, BaseCamp, or MapInstall. All of the OSM maps will be available for viewing on your computer and installing on your GPS receiver.

MapManager - After
MapManager – After
BaseCamp - After
BaseCamp – After
eTrex 30 - After
eTrex 30 – After