uv Unwrap with v=z

I want to create a UV layout for a very complex terrain mesh where i can achieve this sort of effect: http://static3.depositphotos.com/1009905/267/i/950/depositphotos_2674560-Texture-of-wall-of-the-canyon.jpg

To get the pattern to match up on all of the walls of the mesh, I need the unwrapped v coordinates to be proportional to the mesh’s z coordinate.

I cannot think of any way to do this in blender or with a script while still allowing for a reasonable unwrap in the u direction. This seems like a reasonable problem to solve. Any ideas?

Just off the top of my head, you can create a gradient from GIMP, then uv map it to a hill/valley shaped mesh. Use UV Project from view. First set your view looking at the mesh like it is on the horizon. More detailed work should give you something that works well.

You can create this kind of effect, I think, projecting from view, on UV unwrapping, just set previously the viewport at the desired angle, both orthographic or perspective.

EDIT: damned my English, I realized just now that FloridaJo was saying the same, sorry.