Welcome to another World-Machine 2 tutorial! There’s a lot to be excited about in this nifty program, and one of them is the new color maps feature.  If you don’t have a copy of World-Machine, you can always download the trial version.  You can now use the awesome selection tools in World Machine to mix and match color swatches (and even image maps) in order to create your own color overlays for terrains. We’ll be going over all the selection types in the context of mixing colors. Of course, you’re not limited in how you use these; feel free to use them to create new heightfields, mix heightfields together, and whatever else you can imagine.
World Machine Finished File Download

Here's my final rendered terrain.