# Running the Overviewer

## Rendering your First Map

Overviewer is a command-line application, and so it needs to be run from the command line. If you installed Overviewer from a package manager, the command is `overviewer.py`. If you downloaded it manually, open a terminal window and navigate to wherever you downloaded Overviewer. For pre-compiled Windows builds, the command is `overviewer.exe`. For other systems, it’s `overviewer.py`.

What follows in this section is a few examples to get you started. For full usage, see the Usage section.

So, let’s render your first map! Let’s say you want to render your single player world called “My World”. Let’s also say you want to save it c:mcmap. You would type into your command prompt the following:

    overviewer.exe "My World" c:\mcmap

If you’re on Linux or a Mac, you could do something like one of the following:

    overviewer.py "My World" /home/username/mcmap

or

    overviewer.py "My World" /Users/username/mcmap

Those will look for a single player world by that name. You can also specify the path to the world you want to render. This is useful for rendering servers.

Let’s say you have a server installed in /home/username/mcserver. This command will render the default dimension (in the case of Bukkit multiworld servers, the default world is used. You can also specify the directory to the specific world you want to render).

    overviewer.py /home/username/mcserver /home/username/mcmap

After you enter one of the commands, The Overviewer should start rendering your map. When the render is done, open up index.html using your web-browser of choice. Pretty cool, huh? You can even upload this map to a web server to share with others! Simply upload the entire folder to a web server and point your users to index.html!

Incremental updates are just as easy, and a lot faster. If you go and change something inside your world, run the command again and The Overviewer will automatically re-render only what’s needed.

### Specifying a different rendermode

There are a few built-in rendermodes for you to choose from. Each will render your map differently. For example, if you want smooth lighting (which looks really good), you would add `--rendermodes=smooth-lighting` to your command. e.g.

    overviewer.py --rendermodes=smooth-lighting /home/username/mcserver /home/username/mcmap

The rendermodes you have to choose from are:

- normal (the default)

- lighting

- smooth-lighting

- cave

You can specify more than one. Just separate them with a comma!

## Usage

For this section, we assume the executable is `overviewer.py`. Replace that with `overviewer.exe` for windows.

Overviewer usage:

    overviewer.py [--rendermodes=...] [options] <World> <Output Dir>
    overviewer.py --config=<config file> [options]

The first form is for basic or quick renderings without having to create a config file. It is intentionally limited because the amount of configuration was becoming unmanageable for the command line.

The second, preferred usage involves creating a configuration file which specifies all the options including what to render, where to place the output, and all the settings. See The Configuration File for details on that.

For example, on Windows if your Minecraft server runs out of `c:\server\` and you want to put the rendered map in `c:\mcmap\`, run this:

    overviewer.exe c:\server\world c:\mcmap

For Mac or Linux builds from source, you would run something like this with the current directory in the top level of the source tree:

    ./overviewer.py /opt/minecraft/server/world /opt/minecraft/mcmap

The first render can take a while, depending on the size of your world.

### Options

The following options change the way The Overviewer generates or updates the map, and are intended to be things you only have to use in special situations. You should not normally have to specify these options; the default is typically correct.

--no-tile-checks

  With this option, The Overviewer will determine which tiles to render by looking at the saved last-render timestamp and comparing it to the last-modified time of the chunks of the world. It builds a tree of tiles that need updating and renders only those tiles.

  This option does not do any checking of tile mtimes on disk, and thus is the cheapest option: only rendering what needs updating while minimising disk IO.

  The caveat is that the only thing to trigger a tile update is if Minecraft updates a chunk. Any other reason a tile may have for needing re-rendering is not detected. This means that changes in your render configuration will not be reflected in your world except in updated chunks. It could also cause problems if the system clock of the machine running Minecraft is not stable.

  This option is the default unless `--forcerender` or `--check-tiles` is in effect. This option conflicts with `--forcerender` and `--check-tiles`.

--check-tiles

  Forces The Overviewer to check each tile on disk and check to make sure it is up to date. This also checks for tiles that shouldn’t exist and deletes them.

  This is functionally equivalent to `--no-tile-checks` with the difference that each tile is individually checked. It is therefore useful if the tiles are not consistent with the last-render timestamp that is automatically stored. This option was designed to handle the case where the last render was interrupted – some tiles have been updated but others haven’t, so each one is checked before it is rendered.

  This is slightly slower than `--no-tile-checks` due to the additional disk-io involved in reading tile mtimes from the filesystem

  Since this option also checks for erroneous tiles, It is also useful after you delete sections of your map, e.g. with worldedit, to delete tiles that should no longer exist. Overviewer greatly overestimates tiles to be rendered and time needed to complete.

  The caveats with this option are the same as for `--no-tile-checks` with the additional caveat that tile timestamps in the filesystem must be preserved. If you copy tiles or make changes to them with an external tool that modifies mtimes of tiles, it could cause problems with this option.

  This option is automatically activated when The Overviewer detects the last render was interrupted midway through. This option conflicts with `--forcerender` and `--no-tile-checks`

--forcerender

  Forces The Overviewer to re-render every tile regardless of whether it thinks it needs updating or not. It does no tile mtime checks, and therefore ignores the last render time of the world, the last modification times of each chunk, and the filesystem mtimes of each tile. It unconditionally renders every tile that exists.

  The caveat with this option is that it does no checks, period. Meaning it will not detect tiles that do exist, but shouldn’t (this can happen if your world shrinks for some reason. For that specific case, `--check-tiles` is actually the appropriate mode).

  This option is useful if you have changed a render setting and wish to re-render every tile with the new settings.

  This option is automatically activated for first-time renders. This option conflicts with `--check-tiles` and `--no-tile-checks`

--genpoi

  Note

  Don’t use this flag without first reading Signs and Markers!

  Generates the POI markers for your map. This option does not do any tile/map generation, and ONLY generates markers. See Signs and Markers on how to configure POI options.

-p <procs>, --processes <procs>

  This specifies the number of worker processes to spawn on the local machine to do work. It defaults to the number of CPU cores you have, if not specified.

  This option can also be specified in the config file as processes

--skip-scan

  Note

  Don’t use this flag without first reading Signs and Markers!

  When generating POI markers, this option prevents scanning for entities and tile entities, and only creates the markers specified in the config file. This considerably speeds up the POI marker generation process if no entities or tile entities are being used for POI markers. See Signs and Markers on how to configure POI options.

-v, --verbose

  Activate a more verbose logging format and turn on debugging output. This can be quite noisy but also gives a lot more info on what The Overviewer is doing.

-q, --quiet

  Turns off one level of logging for quieter output. You can specify this more than once. One `-q` will suppress all INFO lines. Two will suppress all INFO and WARNING lines. And so on for ERROR and CRITICAL log messages.

  If `--verbose` is given, then the first `-q` will counteract the DEBUG lines, but not the more verbose logging format. Thus, you can specify `-v -q` to get only INFO logs and higher (no DEBUG) but with the more verbose logging format.

--update-web-assets

  Update web assets, including custom assets, without starting a render. This won’t update overviewerConfig.js, but will recreate overviewer.js

## Installing the Textures

Note

This procedure has changed with Minecraft 1.6’s Resource Pack update. The latest versions of Overviewer are not compatible with Minecraft 1.5 client resources.

If Overviewer is running on a machine with the Minecraft client installed, it will automatically use the default textures from Minecraft.

Note

Overviewer will only search for installed client release versions, not snapshots. If you want to use a snapshot client jar for the textures, you must specify it manually with the texturepath option.

If, however, you’re running on a machine without the Minecraft client installed, or if you want to use different textures, you will need to provide the textures manually. This is common for servers.

If you want or need to provide your own textures, you have several options:

- The easy solution is to download the latest client jar to the location the launcher would normally install it. Overviewer will find it and use it.

  You can use the following commands to download the client jar on Linux or Mac. Run the first line in a terminal, changing the version string to the latest as appropriate (these docs may not always be updated to reflect the latest). Then paste the second line into your terminal to create directories if necessary. Then paste the third line into your terminal to download the latest version. `${VERSION}` will be replaced by the actual version string from the first line. These 3 lines can be included in a shell script prior to map generation to ensure the proper textures are always downloaded.

      VERSION=1.17
      mkdir -p ~/.minecraft/versions/${VERSION}/
      wget https://overviewer.org/textures/${VERSION} -O ~/.minecraft/versions/${VERSION}/${VERSION}.jar

  If that’s too confusing for you, then just take this single line and paste it into a terminal to get 1.17 textures:

      mkdir -p ~/.minecraft/versions/1.17/ && wget https://overviewer.org/textures/1.17 -O ~/.minecraft/versions/1.17/1.17.jar

- You can also just run the launcher to install the client.

- You can transfer the client jar to the correct place manually, from a computer that does have the client, to your server. The correct places are:

  - For Linux: `~/.minecraft/versions/<version>/<version>.jar`

  - For Mac: `~/Library/Application Support/minecraft/versions/<version>/<version>.jar`

  - For Windows: `%APPDATA%/.minecraft/versions/<version>/<version>.jar`

- You can download and use a custom resource pack. Download the resource pack file and specify the path to it with the texturepath option.

### If you copy your world before you render it

The important thing to be careful about when copying world files to another location is file modification times, which Overviewer uses to figure out what parts of the map need updating. If you do a straight copy, usually this will update the modification times on all the copied files, causing Overviewer to re-render the entire map. To copy files on Unix, while keeping these modification times intact, use `cp -p`. For people who render from backups, GNU `tar` automatically handles modification times correctly. `rsync -a --delete` will handle this correctly as well. If you use some other tool, you’ll have to figure out how to do this yourself.