Installing Above the Timber 24K Topos on your Apple Macintosh

System Requirements:
  • Intel-based or PowerPC G4 or later Mac
  • OS 10.4 or later
  • 512 MB RAM
  • USB port
Installation steps:
  • Download Garmin MapManager and MapInstall here.
  • Install Garmin MapManager and MapInstall per Garmin's instructions.
  • Download the TGZ file from Above the Timber, either demo or full product.
  • Double-click the TGZ to unzip the file, this will create a gmapi file.
  • Use MapManager to install the gmapi file into MapInstall.
  • If the maps don't appear in MapInstall, a reboot can help.
  • Open MapInstall and select your GPS or logical SD card:



  • Click Continue to go to the map screen

Select the map title using the top-left pull-down. The grid lines show the individual map segments.

Select one or all or as many map segments as desired. The selected segments will show as a numerical count in the Maps () field in the title.
In the above example all but the center map segments are selected (blue). The bar (bottom) shows the memory used (green) and free memory (text).

When finished selecting segments, click Send Maps. This will assemble the map segments into a GPS readable binary file called gmapsupp.img, the only* file your GPS will read.


If you want to add maps from other map titles, use the drop-down list to select more titles and map segments. You cannot add map segments later, doing so will overwrite gmapsupp.img erasing your previous map binary file. Simply stay in this screen and add anything you wish until your card/GPS are full.
* Newer Garmin GPS receivers (CO, OR, MT, Dakota, 62, 78) support AnyName.img. This means you can rename gmapsupp.img to AnyName.img and have multiple binary map files, each must have a unique name. AnyName.img does NOT work on Nuvi's or eTrex, likely other models.

Building the map binary file (gmapsupp.img), the last step, can easily take 10-20 minutes or even an hour, depending on how many map segments you added. So plan on a break once you click Send Maps.
It is strongly suggested that you use a card reader to load the maps, not a USB connected Garmin GPS receiver.

Thanks to Tom Wolf for providing the above Mac screenshots.