[grass, dirt, sand, stone, dark grass, water, grass, wall 1, wall 2, wall 3, wall 4, window 1]
(Not trying to sound like a dick here, I mean this genuinely.)
Tracks in the racing simulator Assetto Corsa are simple 3D model files that have had a few hand modified additions using the editor distributed by the developers.
I wanted to take Elevation data and turn it into a big file of polygons, and then lay a road on top of that using freely available shapefiles that describe roadways, giving the user a smoother surface to drive on. I could either texture polygons using some land use data from the same shapefiles, or using satellite imagery.
You could use a grayscale height map and apply textures based on relative or absolute height. Tallest point on the map? Must be a mountain. Cluster of points lower than the mean or median? Could be a lake or river.
Essentially, it would emulate real world feature distributions.
Just a small concern; looks pretty cool!
Everything is web nowadays! Kudos for making a standalone application.