Last update for DF v34.11.Requests for small island embarks come up fairly often. In one of those topics someone posted a method for reliably generating them. Rather than having it outdated and buried I decided to tweak, update, and give it its own thread. Credit goes to
Grax for the original world generation parameters.
The kinds of islands you can expect to find:
Modified raws and new DF versions cause old parameters to generate different islands so you'll have to find your own islands as described bellow.
Finding Your Own- Paste these world generation parameters into the end of your data/init/world_gen.txt file.
- Run DF and select "Design New World with Advanced Parameters".
- Select "ISOLATED ISLANDS" from the bottom of the list.
- Modify embark points, cavern openness, and similar to taste.
- Generate world.
- Start playing > Legends Mode > export detailed map (whichever one you find easiest).
- Open the exported image file and search for small islands marking their location.
- Start playing > Dwarf Mode > check out the islands you've found.
- Repeat until you find what you're looking for.
Depending on how small you want your island you may have to generate many, many worlds.
Embark SizeKeep in mind that the map only gives a rough idea of the island's shape and size. It's best practice to embark a couple of times to make sure you've got the whole island in the smallest embark possible. To save time make a backup of the world before embarking.
As a rule of thumb assume the island is a tile larger on all edges save those edges bordered by only beaches. The land on non-beach tiles on the local embark screen tend to overlap into neighbouring tiles while beach tiles rarely do. This means they are bigger than they appear.
example embark 1,
example embark 2.
Biomes and SavageryAdd these
before you go looking for an island. If you add these later identical seeds will give you different worlds.
If you want an island with a specific biome then paste one of these into your world_gen.txt after the already pasted world generation parameters:
Swamp,
Marsh,
Forest,
Grassland,
Savannah,
Shrubland,
Desert,
Badlands,
Wasteland,
Hills.
Temperature determines some biome characteristics but unfortunately we have little control over this. If you want a world without glaciers then you can paste
this into your world_gen.txt after the already pasted world generation parameters. All islands will be warm / temperate. Alternatively you can tweak the Minimum / Maximum Temperature settings in Advanced Parameters how you like.
If you want an island with a specific level of savagery then paste one of these into your world_gen.txt after the already pasted world generation parameters:
Benign,
Neutral,
Savage.
Stones and MineralsIf you find the perfect island but it has the wrong minerals then regenerate the world with all the same seeds but a new history seed. This will give you a new mineral layout without changing anything else of importance.
GlaciersIf you decided to generate a world with glaciers only to find they are covering the perfect island then don't fret. You can push them back somewhat by regenerating with the Minimum Temperature set to 75 in Advanced Parameters.
Good and EvilIf you've found the perfect island and want it good/evil aligned then increase the "Desired Good/Evil Square Count in Small Subregions" in Advanced Parameters then regenerate using the same seed. Expect more map rejections and even completely failed maps if set too high. You'll have to regenerate a lot before it randomly picks the island you want to be good/evil.
VolcanoesHunting for small islands with volcanoes is a lengthy process. To increase your odds paste
this into your world_gen.txt after the already pasted world generation parameters. Then set Minimum Volcano Number to 200 in Advanced Parameters. Keep generating new worlds with new seeds checking each volcano on the map until you find one on a small enough island. Volcano location is tied to the world seed so the same seed will always have volcanoes in the same places.
Hopefully I've not missed anything and that you find plenty of decent little islands.