I started off in PSP X and moved to GIMP - I liked PSP's difference clouds a lot better; GIMP's felt too large and undetailed. But everything after getting the basic black-and-white outline of coasts and rivers was done in GIMP. Scale -- d'you mean graphics-wise or land-wise? I'm working VERY large: the full piece is about 12000 pixels wide. Land-wise, this continent is roughly the size of Europe. If you mirrored and rotated Europe to match the major alignment here, and put Spain's western coast along the southern coast, the northern coast would run roughly through Moscow.