mjzemek wrote: I can get the height map using other tools but what about the locations of mex, hydro, start location and reclaimables?
That information as well as additional data is stored in the *_save.lua file. You may want to look at some of the Survival or Zone Control maps to get a better idea what is possible with all the different files that make up a map.
As for the map file, specifically the *.scmap, it is true Hazard X Scenario Editor does read and save that file format, but I have no idea if he had released the file format for that file. That file holds all the geometry as well as all the information that makes a map look good such as the textures, decals, reclaimable rocks and trees (not the dead reclaimable units), lighting, etc.