[Vpmedia]

Exciting stuff with the elevating terrain.

Guess that means it can also be flattened, say, to add an airfield?

The deepest point is 100% black the highest is 100% white.
If youre putting black pixels on the map_h.tga you'll flatten the ground there.
Adding airfields isnt possible with my current knowledge, that part of the map is encrypted even after extraction imho.