I found something in one of the most unlikely places.
A program that generates a whole world
height values, temperature areas, realistic rock and sedimentary layers, biomes/ types of forests, deserts, jungles, swamps, grasslands. Some designated as more wild, or tame.
It generates river patterns and erosions.
And during generation, if it detects any anomalous section, such as a hot desert in a tundra, or a jungle sector carving an unrealistic formation in a mountain, it rejects those world parameters and regenerates them until a realistic parameter is generated.
All of this
And ASCII graphics?
and its just part of a game?!
wha?!
I found this super detailed game called Dwarf fortress. You may think that "oh look at those graphics, this game is so old." yet in fact, it is still in development, and only in alpha. The game is really complicated but alotof fun. The dwarf fortress I got was actually modified with a community made tileset for the game so its not all ASC-ii
The game is like a combination between Civilization, sim city, the sims, rouge, and a make-your own dungeon/fort thing.
But the game isn't why I posted here, what is interesting, is that it generates a whole world for you to play in, and it is really amazing how detailed the process is, you would have to search and read up on it yourself. When a world is created, you can export it in a detailed BMP form, which comes out at a massive 4100x4100 px file.
While This isn't really workable with directly, it can be a very useful source of inspiration for maps, all the way down the rivers and civilizations.
You can get the game with the tileset here: http://mayday.w.staszic.waw.pl/df.htm
The game's website is here:
http://www.bay12games.com/dwarves/
This image has a screenshot of the game during the first stage of starting (choosing where in the world to start your dwarves) You can get the idea how huge it is. But on the local area, each tile of that = at least another whole square in the actual gameplay/actual size level- which has individual trees bushes animals and such.