Yes, I've tried it .. The issue with flattend out basins appears to be: rivers run in straight lines through them ..
I helped myself now by drawing the rivers manually on a separate layer, selecting the negative of the land mass and adding the selection of the rivers to the negative selection. Then I inverted everything and saved it to a channel - tadaa: Rivers Mask
Yet, some questions remain:
Regarding the Mountain Bump Layer:
You say, without it, the mountains would look diminished. I've got an issue with the whole layer (and I guess I'm doing something wrong there, again):
When I use this layer, I get a white hue mountain top on each and every mountain. Since I've got mountains in a desert, snow would just not look credible there ..
So: What am I doing wrong there?
Regarding the Arctic:
You say, after duplicating Arctic 2, you need to apply the Mt Mask. When I apply the Mt Mask, though, upon further duplicating the layer, it won't brighten up the snowy parts anymore, leaving me with a very violet arctic .. I helped myself there by just not applying the Mt Mask - served my purpose .. Yet, I wonder, whether I misinterpreted anything there, too?
Btw.: I just want to stress out once more how incredibly awesome your tutorial is, since it tought me A LOT about the features of Gimp, showing me, what a damn powerful tool Gimp is
Thank you so much for putting it online
Kind regards,
Kai