thx Brandon,
for this moon style landscape i used as base displacement map some geotiffs (http://seamless.usgs.gov/website/seamless/viewer.htm)
did some color normalize, image editing, mixing parts. For the close up did crop through camera, then a sop displace with a simple vop
and handled that to zbrush over for detailing and texturing, back in Houdini using this geo for rock copy stamping...
hope this helps
cheers felix