|This article is about an older version of DF.|
A region or subregion is a named world area, a continuous set of tiles on the world map with the same or similar biomes, and the same alignment. The entire region will be either evil, neutral, or good.
In advanced world generation, regions are classified by size: 24 or fewer tiles is a small subregion, one with 25 to 99 is a medium subregion, and one with 100 or more is a large subregion.
|Biome(s)||Swamp, marsh||Broadleaf forest, coniferous forest, taiga||Grassland, savanna, shrubland||Badlands, rocky wasteland, sand desert||Lake||Tundra||Glacier||Ocean||Mountain|
Temperature, elevation and volcanism
Even if drainage and rainfall are the same in two tiles, if the temperature is different enough that one tile is a tundra or glacier, and an adjacent tile is not, they will be in different subregions.
Similarly, any tile with 300 or more elevation will be a mountain tile, and any tile with less than 100 elevation will be an ocean tile, neither of which form subregions with other land biomes. Volcanism is usually irrelevant for subregions, but a volcano tile adjacent to at least one mountain tile will be generated as if it had an elevation of 400, and will count as a mountain tile.
Additionally, during world generation, lakes will sometimes be generated in the place of tiles that would usually have an elevation higher than 100, in which case they again do not form subregions with adjacent land tiles.