Elevation I: Height Generation

This is giving me a lot of trouble.

Mostly because I don't want to implement a true noise function (like Perlin) into the program, which is how this is done by everyone else.

I'm not everyone else, both because I'm lazy and because I work too hard to stay lazy.

In fact, I'd not mind a true noise function except for the fact that I specifically need to be able to place mountains where I want them, and let the random functions fill in the rest to give a more or less random feel. Too random isn't good either, as the earth itself has many more or less flat plains. We don't always want a totally generated terrain - sometimes we want control.

I still want to do the coastlines mostly by hand, and I want to do them first, rather than pull them out of a generated elevation map. That should come more or less first, thanks to the amount of difference between the rough and fine coasts. Based on how the rivers meet the coastline, though, I'll continue to fiddle with that some. My initial measurements of coastline give a length orders of magnitude shorter than Earth, because Earth's coastline isn't made up of straight line segments.

Once I get the heightmap done, I can work on rivers.

After some experimentation, I settled on a method with GIMP that works fairly well, but could be better. I use this set of brushes that give me a good pseudo-random terrain, then I hexagonize the surface. There are still parts of the surface that look artificial, but I'm hopeful that the erosion cycling will improve this somewhat. It does give me a surface that's a bit rougher than simply using Gaussian blurs. As I've discussed before, real-world terrain is simply not that smooth, and can be quite jagged in places.