Tool to edit Minecraft chunks in bulk
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This program was created originally to change the biome ids of your map. Since then, it has been expanded to make it a more general batch-editor for chunks. Only one chunk is loaded at a time, so the program has a small memory footprint.

Current features include:

  • Change biome ids.
  • Change block ids. Not only blocks placed in the world are replaced, but also blocks in chests, inventories and many other places. See the section below.
  • Convert 1.7 signs to the 1.8 format; fix signs converted incorrectly by Minecraft.
  • Spawn ores in existing chunks.

Screenshot of the tool


See here.


Make sure you have installed Maven.

First, compile Hammer. This library is required for ClimateChanger to compile. Then, download the source code of ClimateChanger (see the sidebar) and run the command mvn install in the directory you have just downloaded ClimateChanger to. You should end up with a runnable JAR file in the newly created target directory.


Before you use any of the features, please read the notes about the feature below.


Execute the command java -jar ClimateChanger.jar. A window should pop up.

Instead of typing the command, on most operating systems you can also right click the jar and select Open with -> Java.

Click the Browse... button to select the level.dat of a world. Add one or more actions and click Execute tasks. The actions will be executed on all dimensions of the world.

Command line

On a headless server, or just prefer to type commands? Start the program like this:

jar -jar ClimateChanger.jar <path/to/level.dat> <action> [and <action> [and ...]]

<path/to/level.dat> is the relative or absolute path to the level.dat of the world.

<action> is the actions to execute. It can be one of the following:

  • changeBiome <fromId> <toId> changes all biomes with the <fromId> to the <toId>. If you use -1 as the <fromId> all biomes will be changed to the given <toId>, so that you end up with a one-biome world.
  • changeBlock <fromId[:fromData]> <toId[:toData]> changes all blocks with the first id to the second.
  • spawnOre <block[:blockData]> <maxRadius> <attemptsPerChunk> <chancePerAttempt> <minAltitude> <maxAltitude> <spawnInBlock,anotherBlock,...> spawns ores of the given type in each chunk.
  • fixSigns <text,moreText,...> will enclose text in brackets on signs that were converted from 1.7 to 1.8, so that the sign reads [text]. Unconverted 1.7 signs will be converted correctly, and signs placed in 1.8 won't be affected.

You can combine multiple actions with the syntax <action> and <action> and <action>.

Biome id replacement

This is the original feature of the program. It simply replaces the biome in the world. This is useful if you want to change the climate of a region: grass color, mobs spawning and weather will change. Actual blocks won't be changed.

Block id replacement

The program allows you to use both block ids and names. Modded block names are supported; the level.dat file is read for name<->id mappings created by Forge Mod Loader.

Block ids and data are replaced in:

  • Blocks placed in the world.
  • Blocks placed in player inventories.
  • Blocks placed in Ender Chests.
  • Blocks placed in tile entities that use the Items tag (in vanilla: chests, dispensers, droppers, hoppers, furnaces, brewing stands)
  • Blocks placed in entities that use the Items tag (in vanilla: horses, minecarts with chest)
  • Blocks placed in entities that use the Item tag (in vanilla: items on the ground, item frames)
  • Blocks placed in flower pots.
  • Blocks being pushed by pistons.

Ore spawning

Ores always spawn in stone. Chance per attempt is always 100. Please note that in vanilla emeralds only spawn in the Extreme Hills biome.

In vanilla Minecraft attempts per chunk is called spawn tries. In the mod Terrain Control attempts per chunk is called frequency and chance per attempt is called rarity.

Ore Max radius Attempts per chunk Altitude
Dirt 33 20 0 - 256
Gravel 33 10 0 - 256
Granite 33 10 0 - 80
Diorite 33 10 0 - 80
Andesite 33 10 0 - 80
Coal 17 20 0 - 128
Iron 9 20 0 - 64
Gold 9 2 0 - 32
Redstone 8 8 0 - 16
Diamond 8 1 0 - 16
Lapis 8 1 0 - 32
Emerald 6 1 4 - 32

Sign conversion

Minecraft 1.8 doewsn't import the Minecraft 1.7 signs correctly. For example, the text [Private], used by Lockette, gets read as a JSON-array with one element Private. Result: the first line of your sign now reads Private and the container is no longer protected!

If you have not opened your map on a 1.8 server yet you can use this program to convert all your signs correctly. If you have already opened your map on 1.8, this program can fix the signs. The program can detect which signs are imported for 1.7, so you only need to specify that Private should be [Private] and the program will do the rest. Signs created in 1.8 are not affected.


The NBT files and the were open sourced by Mojang in 2011 and 2012. The have a don't do evil license. The files have been modified for ClimateChanger.

All other files are public domain. Do whatever you want with it.