A few utilities that convert from raster formats into Garmin vector formats, plus several reverse format converters.
dem2topo: Covered in an earlier post. Takes digital elevation raster files (DEMs) in GeoTiff and a few other formats, and converts them to vector contour lines in shapefile, DXF, and the Garmin Polish Map format (.mp); the latter includes type assignments to the contour lines (major, intermediate, minor). You can choose units and contour line spacings. Great program; I’ve used it a few times.
XYZ2PMF: Command-line program that converts simple ASCII XYZ height files to contour lines. Pretty much requires that you have the expensive (but excellent) GlobalMapper data viewer/converter program. Might have some special feature that fits your needs, but dem2topo is much easier to use.
BMap2MP: Comprehensively covered in an earlier post. Vectorizes a raster image, and converts it to the Garmin Polish Map format (.mp) along with custom data to assign colors to vectorized areas. Works surprisingly well, but not necessarily easy to use; command line only with lots of options. Be sure to read the associated text files for info on how to use it. My Moagu program has a front-end to BMap2MP that makes it somewhat easier to use.
Now, converters that go in the opposite direction:
mp2kml: The oddball program; converts a Garmin Polish Map (.mp) file into the Google Earth KML format. This could be useful for double-checking the accuracy of the .mp file. Perl script, so you’ll need to have Perl installed on your system (ActivePerl is free). Not a Perl user, haven’t tried it. Not updated since 2006, so probably not under active development any more.
ptxt2shp: Converts a Polish Map file into shapefiles, split up by point, line and polygon.
MP2GPXTracks, MP2GPXWaypoints – Java programs that extract tracks and waypoints from an .mp file and convert them to GPX format. The Free GPS utilities website also has a bunch of handy drag-and-drop icon interfaces for GPSBabel, for batch conversion of various GPS waypoint/track/route formats. HT to Martin.