Well, I'm not going to be able to do any more work on this before Wednesday, so I'll post my final version here now. I didn't get as far as I had hoped, but I'm not entirely embarrassed by the final result, so I'll consider it a success.
I tried to rerender it at 4k x 4k, and discovered two things:
- Some of my code is exorbitantly inefficient. The entire map takes less than five minutes to create from scratch at 1k x 1k, but at 4k x 4k, it took over four hours. As nearly as I can tell, none of the procedures should take that much time, so I must have messed something up along the way.
- I haven't caught all of the scale dependencies. At 4k x 4k, the height map is pretty much the same, but the river systems are wildly different. (And for the worse.) This is why I decided to stick with the 1k x 1k version for the final, even though it shows some less-than-pleasant aliasing on the text.
To fix #1, I'll have to look over my code before the next Challenge. For #2, I think that I'm going to have to place coordinate systems on a firmer footing - this might mean explicitly grounding everything geodesically, or handling more chaotic systems (like the rivers) at multiple scales at once.
Anyways, this was fun. Hopefully next month's Challenge will be something equally nice to sink my teeth into.