It uses cGPSmapper to generate IMG's from. It can also generate relief contours from SRTM data for Garmin maps. It has a wiki-based rule engine for specifying how map features should look like (which it then uses to generate Garmin TYP files). GroundTruth is an open source command line application for creating Garmin maps from OSM data.It does not generate maps itself but controls existing tools.

OSM Composer is a GUI for simplifying the process of creating Garmin map images from OSM and SRTM data.osm2mp can create routable garmin maps, see this forum thread for details and download.Mapwel supports OSM files and their conversion to Garmin IMG format with routing. Mapwel is an all-in-one program for GPS mapping.sendmap is a companion program to cGPSmapper for aggregating and uploading map images files.MapCenter is a web interface to cGPSmapper. cGPSmapper can not read OSM files directly. cGPSmapper is a program to convert a textual presentation of a Garmin map into binary map files.GPXSee is an Open Source map/GPS log file viewer with support for Garmin IMG maps.QLandkarte is an Open Source program to display and work with Garmin maps.Mkgmap is an Open Source Java program developed specifically for converting OSM data into Garmin map image files.See OSM Map On Garmin/Download Creating your own maps from OSM data Software Program You can download these files and put them straight onto your device. Some people have done the work of creating Garmin maps for parts of the globe. 4 Using POIs from OSM along with Garmin Maps.3.2 Converting MapSource format maps to Mac OS X format.3.1 What if I have an existing gmapsupp.img file?.2.2 Directions: Creating your map from OSM data.

Gps navigation devices