Get Terrain Texture

Hey guys, quick question:

I'm making a 'minimap' sort of deal and I need to grab a texture of the entire terrain. Is there a simple way of doing this? I haven't been able to find an easy solution.

(I've been setting up an orthographic camera above the terrain and having it render to a texture, and I've come to the conclusion that it is a ridiculous method of accomplishing what I need to do.)

Thank you!