Terrain Generation Ratios
These settings determine how likely different terrain features are.
With the exception of "Isle Spread", the values here are represented as likelihood ratios. You can adjust the numerator by pressing up or down on your keyboard, and you can adjust the denominator by holding shift and then pressing up or down on your keyboard. You can also click the "↻" button to randomly generate a ratio for that setting.
The "ø" button meanwhile holds things in place for large-scale randomization. See the "Randomize Ratios" section of Randomizing And Resetting for more information.
What each setting does
When the map first generates, you get a random assortment of "land" and "ocean" tiles.
Ocean Ratio -- On the next round of generation, these "ocean" tiles are connected together. This setting determines how much they do so.
Land Spread Ratio -- Next, "land" tiles are connected together via Continent Sculpting. The areas generated in this way are then filled in, and the "Land Spread Ratio" determines how much filling is done.
Beach Seed Ratio -- After a bit of cleaning, the next step is to add some random sand tiles to coasts. This setting determines what percentage of the coast tiles ( land tiles adjacent to water) are seeded with sand.
Beach Spread Ratio -- This setting then determines how far the sand tiles spread. Smaller ratios will produce mere coasts, while larger ratios will produce desert-like locations.
Island Chance Ratio -- This setting determines how likely islands are to form in oceans.
Isle Spread -- This setting determines how much those islands will spread.
Mountain Kill Ratio -- On the next round of generation, land tiles will randomly generate either mountain tiles or forest tiles (1/3 chance of either and 1/3 chance of neither). This setting determines which proportion of the generated mountains are removed.
Forest Kill Ratio -- Meanwhile, this setting determines which proportion of the generated forest tiles are removed.
Volcano Chance Ratio -- This setting determines how likely a volcano will form in oceans.
Island to Volcano Chance Ratio -- Meanwhile, this setting will determine how many islands turn into volcanos.
Oasis Chance Ratio -- Inside large sandy spaces, this determines how many "oases" generate (they look a bit like palm trees).
Biome Chance Ratio -- This setting determines how likely "desert" and "ice" biomes are to be seeded. These biomes generate in areas that are bordered to the top and left by mountain tiles.
Ice to Desert Ratio -- This setting will turn generated ice biome tiles into desert biome tiles. I've used it here to convert about half of them since no desert tiles generated naturally.
Desert to Ice Ratio -- This setting, meanwhile, will turn desert biome tiles into ice biome tiles. Useful if only desert tiles generate.
Lava Chance Ratio -- This cluster of settings polishes the biomes and changes their appearance. This setting will generate red "lava" tiles in deserts.
Desert Blend Chance Ratio -- Desert biomes are naturally separated from the rest of the map by "desert blend" tiles. This setting will increase the amount of those tiles that generate.
Snow Chance Ratio -- This setting will generate white "snow" tiles in ice biomes.
Ice Blend Ratio -- Ice biomes are naturally separated from the rest of the map by "ice blend" tiles. This setting will increase the amount of those tiles that generate.
Desert Cave Chance Ratio -- This setting randomly generates yellow "desert caves" in sand-based deserts. (not to be confused with desert biomes).
Harvest Seed Ratio -- This setting determines how likely "harvest" tiles are to generate. "Harvest" tiles are generated by green land tiles that are bordered to the top and left by sand tiles.
Harvest Spread Ratio -- Harvest tiles will then spread out into "Savannah" biomes. This setting determines how likely they are to do so.
Bigtree Chance Ratio -- Inside savannah biomes, a different "bigtree" tile will naturally generate. This setting determines how likely this is to happen.