Last updated 18Jul22

Obtaining OpenStreetMaps (OSM) and Using on Garmin GPSr

If your Garmin GPSr is capable of adding maps, read on …

OpenStreetMap (OSM) is built by a community of mappers that contribute and maintain data about roads, trails, cafés, railway stations, and much more, all over the world. It’s free to use under an open licence. However, it’s not easy to extract relevant portions of the data. It’s easier to use data that has already been extracted by others.

Following are some options to access already extracted data. Each result is slightly different, as slightly different ‘export filters’ have been used.

Choose the map that suits you best, or use several and compare the difference.

With thanks to Beat Oppikofer for showing me the way.

Note: I work in a Windows environment with a Garmin MAP66i GPSr and 16GB µSD card.

Before playing with your GPSr maps, it is strongly recommended that you connect your device via Mass Storge Mode and make a copy of your µSD card drive:\Garmin directory so you can recover from any booboo.

Method 1
(OSM source data updated daily)

  1. Go to https://alternativaslibres.org/en/index.php
  2. In the Sections block, activate Downloads
  3. Activate the Oceania link
  4. Choose the Zone, Type of Map and File desired and activate the Download link
    Eg. Australia, Topographic, File for GPS /Android / QMapShack, Download
    Note the Date of update, so this process can always be repeated to obtain the latest OSM data
  5. Choose the desired download button. This downloads gmapsupp_Australia_Topo.zip of around 1GB
  6. Unzip the gmapsupp_Australia_Topo.zip file
  7. If you already have a gmapsupp.img file on your SD card and want to preserve it, change the name of the downloaded gmapsupp.img file, eg. gmapsuppAustopo7-4-22.img
  8. Copy gmapsupp.img to the SD card on the GPSr into the …\Garmin directory. If doing this via a connected GPSr (USB mass storage mode), takes around 10mins (the file size is around 1.3GB). Would be faster to take out the SD card, insert it in the SD card slot and copy direct.
  9. On the GPSr, do Setup, Map, Configure Maps, OSM-Australia-Topo, Enable
  10. If you would prefer to keep track of the origin of the gmapsupp.img file (eg. using the Date of update from the download), rename …\Garmin\ gmapsupp.img on the SD card. Eg. rename to gmapsuppAustopo7-4-22.img
  11. On the GPSr, configure the new map eg. do Setup, Map, Configure Maps, OSM-Australia-Topo, Enable.

Method 2
(OSM source data updated every now and again)

  1. Go to the OSM maps for Garmin GPS thread on bushwalk.com at https://bushwalk.com/forum/viewtopic.php?t=28893&fbclid=IwAR3HIL4KEVgbwQDi8usviaXjLEGtH4KLirJ39WfgLJr-nqbBVivUba-RJSg
  2. Follow the http://tiny.cc/osm-maps link
  3. Check out the currency of the OSM data and other history details in Mapinfo.txt
  4. Download the .img file(s) you require eg. OSM-AU-NSW.img of around 680MB
  5. Copy the downloaded file to the SD card on the GPSr into the …\Garmin directory. If doing this via a connected GPSr (USB mass storage mode), takes around 6mins
  6. On the GPSr, configure the new map eg. do Setup, Map, Configure Maps, OSM-AU-NSW, Enable

Method 3

  1. Go to https://wiki.openstreetmap.org/wiki/Main_Page for information on OSM
  2. Go to https://wiki.openstreetmap.org/wiki/OSM_Map_On_Garmin/Download
  3. Use the Oceania link in the Contents (or scroll down) to the Oceania section
  4. In the Australia, New Zealand and Oceania row, follow OpenMapChest Note that the data is updated biweekly (later says weekly), so this process can always be repeated to obtain the latest OSM data
  5. Activate the Download Map for SD Card link. This downloads a .torrent file eg. OpenMapChest_Australia_New_Zealand_and_Oceania_2022.04.01_gmapsupp.torrent
  6. If you don’t have a BitTorrent application installed, in the Instructions tab activate the qBittorrent Activate the 32-bit & 64-bit installers link. Activate the qBittorrent Windows x64 download link. This downloads qbittorrent_4.4.2_x64_setup.exe . Install qBittorrent.
  7. Run qBittorent and open the downloaded .torrent file. Set the desired output location and OK. This downloads a zip file eg. OpenMapChest_Australia_New_Zealand_and_Oceania_2022.04.01.zip
  8. Unzip the file. Copy and rename the gmapsupp.img file if you have any file with the same name on your SD card eg. rename gmapsupp.img to gmapsuppOpenMapChest2022-04-01.img
  9. Copy the .img file to the SD card on the GPSr into the …\Garmin directory. If doing this via a connected GPSr (USB mass storage mode), takes around 6mins (the file size is around 605MB). Would be faster to take out the SD card, insert it in the SD card slot and copy direct.
  10. On the GPSr, configure the new map eg. do Setup, Map, Configure Maps, OpenMapChest Australia,, Enable

Which Method? 

  1. If you only want NSW (including the ACT) maps (or a particular State), use method 2
  2. If you want all of Australia, use method 1
  3. If you want Australia, New Zealand and Oceania, used method 3
  4. If you want to compare map features or determine which map you like, use all methods.

Check Out the Differences

One of the benefits of having multiple maps on your GPSr is that they may show different features in an area. You can always turn them on and off via Setup, Map, Configure Maps in your GPSr and examine the differences, but doing so via BaseCamp on your PC gives more screen real estate and easier pan and zoom.

  1. Connect your GPSr to your PC via cable to give Mass Storage Mode
  2. Start BaseCamp. Turn displayed maps on and off by activating the map name via the Maps menu item. This only activates the maps seen in BaseCamp and does not affect the GPSr settings.

Custom Maps

Another mapping technique which may be of interest/use is to add custom maps to your Garmin GPSr. Follow the excellent doco at:

Devices Compatible with Custom Maps
General Guidelines for Creating Garmin Custom Maps
Creating and Loading Custom Maps to an Outdoor Garmin Device