tile-smush

This is a hacked up fork of tilemaker.

It lets you do:

tile-smush foo.mbtiles bar.mbtiles

and get a merged.mbtiles that is the concatenation of the layers in the input files.

It's meant to work on mbtiles produced by mapt. These mbtiles may have overlapping tiles, but the tiles will not have overlapping layers.

This means they can be merged by just concatenating the protobufs, which in theory is a mechanical transformation that should be able to be done very quickly.

Caveats

This was very much built just to enable my personal use case: using mapt to generate thematic layers, then merging them into a single file.

As such, it prioritizes speed and "just enough to work".

• If two or more input mbtiles files contain the same layers, the result is undefined.
• The json metadata value will get its vector_tiles entries merged, but any other entries (such as tilestats) are just dropped on the floor.
  • This JSON munging is done via string manipulation. It's a total hack, but it works. If someone wants to send a PR using rapidjson, it'd be welcome.

Alternatives

You can also use tile-join from Mapbox's tippecanoe. It has a much broader scope, which comes at the cost of being 10-50x slower.

Installing

See tilemaker's instructions.

Copyright

Large chunks of tile-smush come from tilemaker. See its README.md for additional copyright and licensing information.

tile-smush is licensed as FTWPL; you may do anything you like with this code and there is no warranty.