Mkgmap and cGPSmapper perform this process. Creating GMAPSUPP.IMG files (optional): If you would like to directly upload your map onto your Garmin GPS you need to pack your IMG files into an aggregate image file called GMAPSUPP.IMG.Mkgmap will not process arbitrarily large input files, so you probably need to cut the osm file into smaller chunks, most easily with the new splitter.
You should probably use Mkgmap or GroundTruth for this. Convert to IMG file: You need to convert the.Split large area: If your area is a big region or a whole country before compiling OSM data to a garmin IMG file you need to split it with : Splitter.
MapCenter is a web interface to cGPSmapper. cGPSmapper can not read OSM files directly.
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.