Matt - on the list of the cube’s sides, it appears that urban and rural are transposed. Or, maybe I’m missing something with regard to the “near” and “far” designations.
I know, I know. I didn’t create those sylish graphics, I had just scanned a sketch on graph paper and somebody else did the layout. Then there was a revised version made, but both still float around. But it’s not as complicated as that fully drawn cube implies. It can be grasped intuitively in the mind once the main corners are understood.
Actually, the cube drawing is just the opening to this essay I wrote. It’w worth reading, I think.
http://westernrifleshooters.blogspot.com/2010/07/bracken-cw2-cube-mapping-meta-terrain.html