How do all those work? I've been worndering this since I started making maps. I'd appreciate the help ;)
I'm not sure what half the things in that list are, but for the other half:
Alpha could mean one of two things, so...
If you mean the Alpha Sector, those are maps that Virgil and other early-access players made before the game even came out, and they got a place of honor there.
If you mean Alpha as in SetImageColor, then it tells you how see-through something is. With 255 being normal, can't-see-through-it, and 0 being completely invisible. You can make ghost-like units by setting it somewhere halfway.
As for the Arc Eternal maps, I'm guessing you're asking things like "How do the pyramids on Meso work?" and other such questions. There's a way you can check that for yourself, taking any game save and loading it with the editor, which lets you look at the CRPL scripts that were used to create it. This works for the story missions, and for any mission at all, so if someone on Colonial Space uses interesting CRPL, you can check that out too. The link for that is:
http://knucklecracker.com/wiki/doku.php?id=crpl:examine_map_resources
'Proc' means procedural. These texture combinations were randomly generated before the game launched. I've never used overlays but someone told me it was meant to make map making easier by loading an image. What you probably mean with 'alpha' is the alpha value for the overlay (transparancy).
Proc1,Proc2, and the rest of the names in that list -- they are texture themes. Pick one and click "set theme" -- and it helps if you already have multiple terrain levels on your map. The "theme" is basically a set of 10 textures for the 10 terrain levels. The Map Textures button lets you edit them individually.
The Alpha on the edit menu bar next to Edition Overlay / Load is the alpha transparency level for the overlay image. You can load a picture into the map editor if you have something you want to use as a guide for building the map. It's only used in the editor and won't be in the final map. The overlay image is aligned to the bottom left corner of the map and is not scaled. A map cell is 8 pixels, so if you want your image to be the same size as the map -- for a 120x60 map you'd need a 960x480 image.
Thanks for the help. Might use those in future maps.