This is the result of a little processing sketch i wrote. It takes any bitmap heightfields like the one in the images and turns it into a stl file that can be printed on a makerbot

http://www.local-guru.net/blog/2010/03/28/generating-3d-objects-from-heightfields

download and run the processing sketch from my blog post, scale and rotate the stl object in blender let blender remove the doublicate vertices to simplify the mesh slice it using skeinforge and print it on your 3D-Printer