Compatibility
Minecraft: Java Edition
Platforms
Tags
Creators
Details
Required Dependancy
This Datapack requires More Density Functions by Klinbee installed to function!
What Does It Do?
This datapack adjusts the Overworld terrain generation to create 1024x1024 block "islands" of regular generation surrounded by forced equally sized deep oceans.
This attempts to create a similar feel that the limited world sizes of Legacy Console Edition had while still enabling infinite generation.
The datapack also roughly halves the size of the Temperature noise map, along with making Ocean Monuments significantly more spread out.
What Doesn't It Do?
This datapack does not replicate legacy console world generation, biomes, or structure generation.
It also does not attempt to make rare structures/biomes more common to compensate for the increased frequency of Oceans. Things like Mushroom Islands and Woodland Mansions are going to be exceptionally rare, even moreso than they already are.
How Does It Look?
(All screenshots are taken from a world with seed -1818743322698042723 on 1.21.1)
The islands are square, however the coastlines are not perfectly square and appear "fuzzy" or wobbly.
Figure 1: Ideal Island

Taken from a map export done using Xaero's World Map. Map is a 1/4th of a 1:1 pixel:block ratio. See the gallery for the 1:1 verison.
Note the imperfect "fuzzy" square shape, along with the noticable "shelf" that generates past the coast.
However, the datapack does not make an attempt to avoid ocean generation within "islands". This can not matter like with Figure 1, could take a chunk out of the island (Figure 2), or just entirely obliterate the island (Figure 3).
Figure 2: Bitten Island

Figure 3: "Island"

How Does It Do?
Nerd Talk
Each island is a 2048x2048 section of the overworld consisiting of an inner "island" of normal continentalness noise, a transition period, and an outer "ocean" where the Continentalness is forced to -0.75
The "transition period" starts at a distance of 464 and ends at a distance of 592, through which the returned Continentalness is linearly interpolated between the regular noise and -0.75.
The distance itself is calculated as the maximum between the absolute values of X and Z from the center of the 2048x2048 section.
The datapack makes use of More Density Functions modulo to enable repeating the sections, alongside the X and Z functions.
How Does It Behave With Others?
As a general rule, if the mod/datapack doesn't adjust the fundimental terrain shape, it should work perfectly.
More In-Depth Compatibility
Absolutely*
- Biome Mods/Datapacks (Think like No Man's Land or Oh The Biomes We've Gone)
- Structure Mods/Datapacks
- Standard Content Mods
- Mods that only touch worldgen for structures or ores should work without issue.
*It's highly dependant on the mod/datapack, but generally these types don't mess with what Legacy Islands does.
Also both mentioned mods are perfectly compatable.
Technically
- Dimension Mods/Datapacks (The datapack only touches the Overworld.)
Probably Not.
- World Generation Datapacks (Think Continents, Lithosphere, or Tectonic)
- Most world generation packs either overwrite the vanilla Continentalness file (
minecraft:overworld/continents) or outright change the Overworld to use a different noise map.
- Most world generation packs either overwrite the vanilla Continentalness file (
- Generation Overhaul Mods (Think completely custom generation like Moderner Beta, unfortunately.)
- Mods like this usually implement their own world types that don't use data driven generation.


