"SE5MapCreator" is visual GUI to create and edit (previously created by the same application) maps for SE5. It can't edit the maps generated by the game, as the encryption used by Malfador hasn't been released, or at least I don't know it.

This Map Creator / Editor uses the mapcompiler released by MM.
This Map Creator couldn't have been written without the base put by Rick (rick@gibbed.us) and his map creator for Space Empires 5 ((c) Malfador Machinations 2006) (more info on http://www.spaceempires5.com/en-US/project/rmg).