This format can...
read and write waypoints
This format is derived from the xcsv format, so it has all of the same options as that format.
Mapconverter is a format that is read by Mapopolis.com's mapconverter application.
Mapconverter is an application used to create userland maps and map data for Mapopolis.com's Mapopolis program. The mapconverter format is essentially waypoint data prepared in a format that the mapconverter application will accept.
The steps for using GPSBabel and Mapconverter go something like this:
Step 1: Create a mapconverter file using gpsbabel.
gpsbabel -i geo -f geocaching.loc -o mapconverter -F foo.txt
Step 2: Launch mapconverter.exe and choose foo.txt as your input file. Click the begin button to have mapconverter process foo.txt.
If all goes successfully, you should have a file called "foo.pdb" ready for syncing with your PDA. Put it wherever Mapopolis thinks it should be on your PDA.
GPSBabel will write the name of its own output file in the output file it creates as the input for Mapconverter. Mapconverter will replace the extension of this filename with ".pdb".
The PocketPC version of Mapopolis doesn't notice files with the ".pdb" extension. To make this work, change the extension to ".mlp" when copying the mapconverter output to your PocketPC PDA.
Mapconverter only works with Mapopolis version 3.x. Mapopolis version 4 will refuse to load mapconverter maps. There is no known work-around for this at the time of this writing.
Mapconverter is no longer available from the Mapopolis website. If you need a copy of mapconverter, ask on your local GPS Software discussion forum and I'm sure someone will have it. As far as I know, It was never actually acknowledged/supported by Mapopolis to begin with.