Procedural River Maps by WASasquatch (NWDA) Procedural River Maps was created by WASasquatch (Jordan Thompson) with a need to create a drop in solution to creating rivers without cluttering a project building a river from the ground up. PRM outputs an RGB map which can be split into their appropriate corresponding maps. mapsprmproceduralriverPRM outputs a Valley Map, Banks Map, and River Map for displacement usage in your terrains.