Dynmap Scraper

A tool written in Python for downloading maps as images from MC server Dynmaps.

Using

Dependencies

• Python 3.9+ (64-bit, except for very small maps)
• The following python modules (can be installed with pip):
  • tqdm
  • Pillow
  • requests
  • docopt (for CLI)
• A reasonable amount of RAM (A 6000×6000 map at maximum zoom will take around 2.5 GB of RAM)

Guide

CLI

With the dependencies installed (including docopt), the CLI can be run by executing cli.py with python3.9 (e.g. python3.9 cli.py). This will fail if no additional arguments are provided, though help information can be produced by running it with the --help flag (e.g. python3.9 cli.py --help).

To have the same output as the default output from the manual section (i.e. just executing main.py directly) use the following:

python3.9 cli.py "http://dynmap.elgeis.com:2121/" "8302018" --output=dynmap.png --cache=cache --size=worldborder --zoom=0

Note that everything from --output onwards is optional in this case as it is the same as the default values, so

python3.9 cli.py "http://dynmap.elgeis.com:2121/" "8302018"

would also work. More information on what this in specific does is available in the next section (“Manual”).

Manual

Once the aforementioned dependencies are installed (except for docopt, which is not necessary for this method), this can be run by executing the file main.py with python3.9 (e.g. python3.9 main.py). This will obtain a map cropped to the world border at maximum resolution from http://dynmap.elgeis.com:2121/ in world 8302018 and save it to dynmap.png, using the folder cache for cache.

Lines 19–24 can be altered to change what is done. Make sure to keep quotation marks around the options that already have it by default (unless otherwise specified) and do not remove the commas at the end of each line.

Link (line 19)

This changes what Dynmap server is actually contacted for the content. The default value is for the Elgeis Minecraft server. In general, you can just copy the link in your browser and it will work fine (though make sure to include a trailing slash).

World (line 20)

This changes which world the map is downloaded from. The available worlds can be seen in the Dynmap sidebar.

Output (line 21)

This is where the map file will be saved. The format of the file is inferred from the extension (so changing this to dynmap.jpg will save it as a JPEG file instead).

Cache (line 22)

This is where an optional cache can be saved. This will speed up subsequent downloads if you are downloading overlapping regions and it will allow you to resume where you left off if the program crashes.

The cache is quite large and will use up approximately as much space as the image itself (or actually a bit more than that). If you do not desire a cache you can set this line to None (DO remove quotes for this one, otherwise it will just use a folder called None instead, but do keep the comma at the end).

Size (line 23)

This is which region of the world will be downloaded. The default value of None will attempt to obtain the worldborder from the Dynmap, though this may fail depending on whether the world has a worldborder or not.

To specify a region, replace this with ((x₁, x₂), (z₁, z₂)) (do not put any quotation marks), where x₁ is the x-coordinate of the left (west) edge of the region, x₂ is the x-coordinate of the right (east) edge of the region, z₁ is the z-coordinate of the top (north) of the region, and z₂ is the z-coordinate of the bottom (south) of the region. Make sure that x₁ < x₂ and z₁ < z₂.

Zoom (line 24)

This is the level of zoom that is used, with 0 being maximum zoom and 5 being minimum zoom. Each additional level of zoom scales down the resolution by a factor of 2.