Another update. I shouldn't have, but the unfinished climates are bugging me to no end. So, I installed GIMP and downloaded Charerg's 6-step script, hoping that would help. I got the script running - and even hacked off a pixel in the top left corner, as instructed. The script started strong, creating a few more layers, but then I didn't really see anything happening. Task Manager told me GIMP kept using between 4 and 20% of my Xeon processors, and about 10GB of RAM - but after about forty minutes it gave up, leaving me with a white map with a couple of purple patches over the driest, hottest places, and grey over the absolutely coldest regions.

Obviously, I'm doing something wrong, since none of the three script alternatives work. :/

I think it has to be the colors. I've copied and pasted example maps from the Köppen tutorial thread into Photoshop and used the color picker to create my swatches, but now that I check I see that it hasn't been precise enough. Well, I haven't given up! Luckily, Charerg posted RGB values for all zones in his script post, so I'll add them manually, repaint everything using PENCIL, and try again.

-Niels