This approach might be more feasible in the smaller scales. It also works with a video game software called Auran Trainz, at least through Trainz Railroad Simulator 2004 (aka TRS2004.)
In the game's terrain editor which is called surveyor, the keystroke combination Alt-MMMG ("Make Me a Map George") starts a terrain-generating routine. You can watch the mountains rise up out of the flat, featureless grey grid plane! When you're happy with the topology, then you start with the scenicking and track laying, etc.
This is a one-player "sandbox" type video game with no objective toward winning or losing. For years i've been hoping they would add an economics engine, where it costs money to level mountains, place bridges, lay track, and run trains. Sort of like Sid Meier's Railroads, but with detailed 3D graphics and more of a detailed operational approach. That would make the game a lot more interesting, at least for me! Good topic!!
