After looking at some of garbled's (Tim's) attempts at making a topographic map, njh told me to look at a program called terraform. For debian users apt-get install terraform, for the rest of the world http://terraform.sourceforge.net/. It creates topographic maps with heaps of cool options, you can use: Perlin Noise Spectral Subdivision Random All of these look very convincing =). You can specifify x and y, and can even apply filters like erode. Not to slow down the work done by Mark and Tim, but isn't this sort of what you are trying to implement? Perhaps you could take some iedas from this or even use it =). dnh