I'm trying to create a map similar to Outset island in Loz: Wind Waker. Here is an example of what I'm trying to create:
As you can see, the roads more or less have dedicated tris. However, when I look at the UV data, it looks like a complete mess:
For reference, this is the texture without any overlays:
I have no idea how to go about creating a similar effect in my own game -- are there any tools I can use? What is this technique called?