To_the_ceiling

Move an heightmap to the ceiling, the highest pixel goes to 1. The proportions remain unchanged. It means that the shape is just moved.

For moving an heightmap to the ground, you can use https://share.allegorithmic.com/libraries/2219

Important update 25/09/2016: Now you can use this node is highest resolution without crashing/freezing, due to a huge improvement of some dependencies. And much faster, like 200x faster with 2K heightmaps.