Desirability II: Where Do All the People Go?

I've been getting way behind on posting, largely because of my struggles with getting the climates to fall out just right. I know, I know, there's a fair bit of ad hoc going on here. But I've had some trouble in the past with my climates swinging directly from harsh rainforest to harsh deserts. I've got to figure out some methods to smooth that out.

First of all, I can lower the temperature model. It's not just the rain - although that hurts too. Temperature is an odd bird, especially trying to go from this chart on Cartographer's Guild to some actual numbers that I can use for my model. I may need to step back to those isotherms and see if I can build up the coherent model from that. I've been trying several different math functions to try and get smooth interpolation, but I haven't found one that works.

Koppen map

I want to see more green here. The real world has a lot of green (which is the C climate type, really good for crops and such). Some tweaking improved this. However, there's still very little D (boreal), denoted by turquoise. This isn't really a problem, exactly, but I wonder how much of this is due to the terrain/climate system and how much is due to the errors of the model.

However, I can take another look at my "desirability" maps. I still have some tweaking to do to make the right recipe, and then do it again for all the races I want to include! Here is where the climate distribution shows its ugly belly.

The greener, the better

It seems at first glance that there's a lot of empty space. Everyone wants coastline, of course, but no one wants to be in the desert (humans, anyway; I like the idea of desert orcs).

Things to think about:

• Why did the terrain generator make all my coasts so low? Good coastal access should be a bit rarer - as it is, 98% of coastal hexes are lower than 500 ft.
• How do different climates affect desirability rating? How about resource availability (which system will take years to fully develop, of course)? How about other cities and their cross-country roads?
• How should I start placing cities on here once I like the maps? Of course, I can start work on that model right away, since it's all generated, and refine them in tandem.