By Andrew Brown and contributors

http://github.com/brownan/Minecraft-Overviewer

Generates large resolution images of a Minecraft map.

In short, this program reads in Minecraft world files and renders very large resolution images. It performs a similar function to the existing Minecraft Cartographer program but with a slightly different goal in mind: to generate large resolution images such that one can zoom in and see details.

See some examples here! http://github.com/brownan/Minecraft-Overviewer/wiki/Map-examples

(To contact me, send me a message on Github)

• Renders large resolution images of your world, such that you can zoom in and see details
• Customizable textures! Pulls textures straight from your installed texture pack!
• Outputs a Google Map powered interface that is memory efficient, both in generating and viewing.
• Renders efficiently in parallel, using as many simultaneous processes as you want!
• Utilizes 2 levels of caching to speed up subsequent renderings of your world.
• Throw the output directory up on a web server to share your Minecraft world with everyone!

This program requires:

• Python 2.6 or 2.7 <http://python.org/download/>
• PIL (Python Imaging Library) <http://www.pythonware.com/products/pil/>
• Numpy <http://scipy.org/Download>
• Either the Minecraft client installed, or a terrain.png file. See the Textures section below.

I develop and test this on Linux, but need help testing it on Windows and Mac. If something doesn't work, let me know.

Before you dive into using this, just be aware that, for large maps, there is a lot of data to parse through and process. If your world is very large, expect the initial render to take at least an hour, possibly more. (Since Minecraft maps are practically infinite, the maximum time this could take is also infinite!)

If you press ctrl-C, it will stop. The next run will pick up where it left off.

Once your initial render is done, subsequent renderings will be MUCH faster due to all the caching that happens behind the scenes. Just use the same output directory and it will only update the tiles it needs to.

There are probably some other minor glitches along the way, hopefully they will be fixed soon. See the Bugs section below.

The Overviewer uses actual textures to render your world. However, I don't include textures in the package. You will need to do one of two things before you can use the Overviewer:

• Make sure the Minecraft client is installed. The Overviewer will find the installed minecraft.jar and extract the textures from it.
• Install a texture file yourself. This file is called "terrain.png" and is normally found in your minecraft.jar file (not "Minecraft.jar", the launcher, but rather the file that's downloaded by the launcher and installed into a hidden directory). You can also get this file from any of the third party texture packs out there.

With the Halloween update, biomes were added to Minecraft. In order to get biome-accurate tinting, the Overviewer can use biome data produced by the Minecraft Biome Extractor tool. This tool can be downloaded from: http://www.minecraftforum.net/viewtopic.php?f=25&t=80902

If the "biomes" folder is present in the world directory, then the Overviewer will use the biome data to tint grass and leaves automatically -- there is no command line option to turn this feature on. If this folder does not exist, then the Overviewer will use a static tinting for grass and leaves.

The C Extension for Overviewer is completely optional. It provides a higher quality image compositing function that looks better on maps with lighting enabled, and a slight performance boost.

If you downloaded Overviewer as a binary package, this extension may be already compiled for you. Overviewer emits a warning if the extension is not found, but will still work fine.

If you have a C compiler and the Python development libraries set up, you can compile this extension like this:

python setup.py build

Note that you need the development headers for your version of Python installed, look for a package named 'python-dev', 'python-devel' or similar. Also, some Python distributions do not install "Imaging.h" and "ImPlatform.h" properly. If you get errors complaining about them, you can get them from the PIL source, or at <http://svn.effbot.org/public/tags/pil-1.1.7/libImaging/>. Just put them in the same directory as "_composite.c".

To generate a set of Google Map tiles, use the gmap.py script like this:

python gmap.py [OPTIONS] <World # / Name / Path to World> <Output Directory>

The output directory will be created if it doesn't exist. This will generate a set of image tiles for your world in the directory you choose. When it's done, you will find an index.html file in the same directory that you can use to view it.

Important note about Caches

The Overviewer will put a cached image for every chunk directly in your world directory by default. If you do not like this behavior, you can specify another location with the --cachedir option. See below for details.

-h, --help

Shows the list of options and exits

--cachedir=CACHEDIR

By default, the Overviewer will save in your world directory one image file for every chunk in your world. If you do backups of your world, you may not want these images in your world directory.

Use this option to specify an alternate location to put the rendered chunk images. You must specify this same directory each rendering so that it doesn't have to render every chunk from scratch every time.

Example:

python gmap.py --cachedir=<chunk cache dir> <world> <output dir>

--imgformat=FORMAT

Set the output image format used for the tiles. The default is 'png', but 'jpg' is also supported. Note that regardless of what you choose, Overviewer will still use PNG for cached images to avoid recompression artifacts.

-p PROCS, --processes=PROCS

Adding the "-p" option will utilize more cores during processing. This can speed up rendering quite a bit. The default is set to the same number of cores in your computer, but you can adjust it.

Example to run 5 worker processes in parallel:

python gmap.py -p 5 <Path to World> <Output Directory>

-z ZOOM, --zoom=ZOOM

The Overviewer by default will detect how many zoom levels are required to show your entire map. This option sets it manually.

You do not normally need to set this option!

This is equivalent to setting the dimensions of the highest zoom level. It does not actually change how the map is rendered, but rather how much of the map is rendered. (Calling this option "zoom" may be a bit misleading, I know)

To be precise, it sets the width and height of the highest zoom level, in tiles. A zoom level of z means the highest zoom level of your map will be 2^z by 2^z tiles.

This option map be useful if you have some outlier chunks causing your map to be too large, or you want to render a smaller portion of your map, instead of rendering everything.

This will render your map with 7 zoom levels:

python gmap.py -z 7 <Path to World> <Output Directory>

Remember that each additional zoom level adds 4 times as many tiles as the last. This can add up fast, zoom level 10 has over a million tiles. Tiles with no content will not be rendered, but they still take a small amount of time to process.

-d, --delete

This option changes the mode of execution. No tiles are rendered, and instead, cache files are deleted.

Explanation: The Overviewer keeps two levels of cache: it saves each chunk rendered as a png, and it keeps a hash file along side each tile in your output directory. Using these cache files allows the Overviewer to skip rendering of any tile image that has not changed.

By default, the chunk images are saved in your world directory. This example will remove them:

python gmap.py -d <World # / Path to World / Path to cache dir>

You can also delete the tile cache as well. This will force a full re-render, useful if you've changed texture packs and want your world to look uniform. Here's an example:

python gmap.py -d <# / path> <Tile Directory>

Be warned, this will cause the next rendering of your map to take significantly longer, since it is having to re-generate the files you just deleted.

--chunklist=CHUNKLIST

Use this option to specify manually a list of chunks to consider for updating. Without this option, every chunk is checked for update and if necessary, re-rendered. If this option points to a file containing, 1 per line, the path to a chunk data file, then only those in the list will be considered for update.

It's up to you to build such a list. On Linux or Mac, try using the "find" command. You could, for example, output all chunk files that are older than a certain date. Or perhaps you can incrementally update your map by passing in a subset of chunks each time. It's up to you!

--lighting

This option enables map lighting, using lighting information stored by Minecraft inside the chunks. This will make your map prettier, at the cost of update speed.

Note that for existing, unlit maps, you may want to clear your cache (with -d) before updating the map to use lighting. Otherwise, only updated chunks will have lighting enabled.

--night

This option enables --lighting, and renders the world at night.

Within the output directory you will find two things: an index.html file, and a directory hierarchy full of images. To view your world, simply open index.html in a web browser. Internet access is required to load the Google Maps API files, but you otherwise don't need anything else.

You can throw these files up to a web server to let others view your map. You do not need a Google Maps API key (as was the case with older versions of the API), so just copying the directory to your web server should suffice. You are, however, bound by the Google Maps API terms of service.

http://code.google.com/apis/maps/terms.html

Image files taking too much disk space? Try using pngcrush. On Linux and probably Mac, if you have pngcrush installed, this command will go and crush all your images in the given destination. This took the total disk usage of the render for my world from 85M to 67M.

find /path/to/destination -name "*.png" -exec pngcrush {} {}.crush \; -exec mv {}.crush {} \;

Or if you prefer a more parallel solution, try something like this:

find /path/to/destination -print0 | xargs -0 -n 1 -P <nr_procs> sh -c 'pngcrush $0 temp.$$ && mv temp.$$ $0'

If you're on Windows, I've gotten word that this command line snippet works provided pngout is installed and on your path. Note that the % symbols will need to be doubled up if this is in a batch file.

FOR /R c:\path\to\tiles\folder %v IN (*.png) DO pngout %v /y

This program has bugs. They are mostly minor things, I wouldn't have released a completely useless program. However, there are a number of things that I want to fix or improve.

For a current list of issues, visit http://github.com/brownan/Minecraft-Overviewer/issues

Feel free to comment on issues, report new issues, and vote on issues that are important to you, so I can prioritize accordingly.

An incomplete list of things I want to do soon is:

• Improve efficiency
• Rendering non-cube blocks, such as torches, flowers, mine tracks, fences, doors, and the like. Right now they are either not rendered at all, or rendered as if they were a cube, so it looks funny.
• Some kind of graphical interface.
• A Windows exe for easier access for Windows users.