[simonh]

Minecraft also has biomes, which customise the terrain generation to produce regions of a particular type of terrain like forest, desert, sea, etc and some intermediary biome types like beaches. I don't know how it distributes the main biomes, but it may use one noise algorithm for that and another within each biome. Plus applying some rules to handle the borders between biomes. There is a lot more to it that just "It's Perlin noise".