Making your own Garmin GPS maps

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2012 May -

If you have a Garmin Oregon, Dakota, or Colorado, you can convert any map into a JPEG format, georeference it, and load it into your Garmin. Garmin actually provides instructions on how to do this.

I have seen other web sites describe loading rasters into older Garmin handhelds but have not investigated it myself.

2010 November -

A year ago I was getting ready for a backpacking trip. I rode shotgun most of the way from Gold Beach, Oregon to Point Reyes in California, while working on a topo map of Marin county. When I ran into error messages that I could not decipher, I tucked the laptop away and used my old low-res 1:250K Garmin maps. It was a wonderful backpacking trip, lacking as it did the disruptions of GPS wonderment.

When I got home, I ordered the Garmin Topo 1:24K maps for the western US. That put my interest in Garmin maps on hold for another year.

Then 2 weeks ago I went Halloweeding and discovered the Garmin's owned by BSWCD have no maps! I must fix this! SO now I am creating a topo map for Benton County, Oregon.

2009 February - you might also want to Make route files for your Garmin

2007 November- I have actually successfully built a building footprint layer for Corvallis Oregon and loaded it into my Garmin ETrex Vista HCX.

Benton County, Oregon topographic map

The goal: a 1:24k or better topo map in Garmin format suitable for use on an eTrex with 24MB of flash memory.

Developing Benton County topo map

My long term objective

I use ArcGIS software on a daily basis and I write software. I'd really like to be able to produce maps directly from ArcGIS. I realize this is outside the scope of most of the people likely to find this page. Not to worry, so far I have only found time to use freely available tools to do the actual Garmin maps.

The steps would be

  1. Collect data required for the project.
  2. Process into a usable format with ESRI tools.
  3. Convert it into the format used by Garmin in mapping GPS receivers.
  4. Upload it to the Garmin.

An earlier version of this page said I'd like to be able to upload finished maps to a web server, and be able to distribute the maps with a plugin that would allow directly loading them into the Garmin. In my experience this will never happen because maps are loaded as sets, so you can't add just one map to the existing set. You have to create the set in Garmin MapSource and then send the complete set to the device.

Anyway - there is a site ( to exchange completed maps and I'd probably use it rather than duplicate their efforts.

A simpler thing than making full maps is to create POI's. Garmin POI loader

Garmin map format

The format used by the Garmin devices is proprietary and has not been released. The programmers had to reverse engineer Garmin's format to write the programs that are able to create Garmin maps. That's why there are only a couple programs capable of generating Garmin map files.


The current crop of Garmin devices use vector data only. That means you cannot upload rasters such as scanned paper maps and USGS DRG topos to the Garmin devices.

With the release of the Garmin Oregon this may have changed.

This program claims to be able to work with rasters. I have not tried it yet. It works with only a few models, and it requires the cGPSmapper program.

Another one is bmap2ms (

Tutorial for Topo maps at GPSFileDepot: NEEDS cGPSmapper, no longer available.

Available tools

GPSMapEdit -- $55 MapWel -- $45/basic $90/advanced MOAGU -- for loading rasters into Garmins TopoFusion


GPSMapEdit is designed for visual authoring of GPS-maps in various proprietary cartographic formats, including Shapefiles, cGPSMapper, GPX, OziExplorer maps, Garmin, Magellan, ALAN Map 500, Holux. Handling of projected shapefiles is limited.


cGPSmapper-- This was the best choice for a long time but it's now "end of life".

GPSTrackMaker Free. Transfers data between a computer and many different GPS receivers. Does not support maps, it supports waypoints, tracks and routes. You can view rasters as backgroups to help create vector data. Website is a data source for maps of Brazil.

mapdekode There is not much information at the website unless I am missing something.

OZIexplorer There are Windows and WindowsCE versions. There is a cool 3D version. There are free and affordable (around $100) versions. The CE version costs a few dollars more. This is moving map software. It supports waypoint/track/route transfers. There is also a Map Merge utility program here.

With the trial/free version you can only use BMP files as a source for a map image. After I calibarte the BM{ image I can't change from WGS84, not sure if this is a limitation of the trial version.

MapSource Let's not forget that I do have a licensed copy of Garmin MapSource available. I also have a collection of Garmin data including City Navigator, Metro, Roads and Rec, and Topo for US, Canada, and Europe.

Update 1/2008, just heard about this one from the [GPS Maps mailing list]. "MapMan is the only map making application to bring you Automapit, automatic feature recognition to take the drudge out of map making."


Topo maps -- If you want to make a topographic contour layer the tool to use is DEM2TOPO. (Update 7/2008)

Another approach is to use the program Mapwel which is described on this page


MapExtract Freeware. "Simply, it is a tool which help you to extract selected piece(s) from large map(s) and load it(them) into your Garmin GPS for minutes. This will change the speed of map refreshing on the screen and certainly you'll not miss next turn waiting to see where you are :-) This software can be used also as map data preprocessing and postprocessing tool for cGPSmapper - Garmin MapSource maps creator." Yahoo! mapextract group

POI Loader is free software from Garmin that lets you transfer POI files to the GPS receiver.

Map preparation

So far based on the above notes it looks like I need to be looking at cGPSMapper and possibly MapDekode to do the conversion of shapefiles to Garmin IMG files.

In ArcMap I create a map containing the data that I want to transfer to the Garmin.


The Garmin uses unprojected WGS84 internally.

Vector data

Points will be transferred to a POI file. For symbolization I want to have a set of Garmin graphics to use in ArcMap (or QGIS). Is that possible?

Lines Polygons

Garmin format

Resolution limited to 2.4 m


MapDekode is primarily a tool to convert OZIexplorer maps into Garmin format. MapDekode can also convert GPSTrackMaker files into Garmin format.

Max file size is 1MB Suggested limit is 500kB


Map authoring guide, lots of links

Web-based tools

Garmin will now officially let you transfer rasters to a few devices. (These models: Dakota, Oregon, Colorado) For more information see: Garmin Custom Maps and their forum. I don't have a Dakota, Oregon, or Colorado yet so it is not terribly exciting to me.

Maps for Garmin GPS Receivers Includes a HOWTO section

Make custom TOPOs for your Garmin, step by step guide. Uses DEM2TOPO and GPSMapper

Map authoring guide

Map Authors group on Yahoo groups

MapCenter has maps that folks have created.


google ozi Google Earth connection to OziExplorer (extracts images from GE)

Mobile Atlas Creator

Trek Buddy J2ME software for mobile devices (Blackberry, Android, etc)