Thank Boyd! I didn't realize that it is possible to use GPSMapEdit to create the .mp format file. Use File >> Import.
Also, this link: https://kavehjamali.com/polish-format-map-mp/
has good info about .mp formats.
He mentions MicroGISEditor - map editor. I haven't tried it but it might be a good alternative to GlobalMapper.
http://micro-gis.com/index.php/editor-en.html
I agree about the term "Custom Map". Maybe we need to call them "Personal Maps" or something.
Also, this link: https://kavehjamali.com/polish-format-map-mp/
has good info about .mp formats.
He mentions MicroGISEditor - map editor. I haven't tried it but it might be a good alternative to GlobalMapper.
http://micro-gis.com/index.php/editor-en.html
I agree about the term "Custom Map". Maybe we need to call them "Personal Maps" or something.