Tile Tools

Collection of tools useful for navigating Mapbox (and similar) tiles.

Most of these tools were written by Mapbox in JavaScript. I've ported them into Python with minimal modification.

Contents

tilebelt

Utility functions for working with tiles.

This is a complete Python port of Mapbox's @mapbox/tilebelt.

There are some minor differences in the API. See the submodule readme for more details.

cover

Given a GeoJSON Geometry and a zoom level, generate the minimal set of Mapbox (x, y, zoom) tiles that cover this geometry.

This is a re-implementation of Mapbox's @mapbox/tile-cover. The implementation started out as a port, however the originally library is not passing all of its own tests. The API has been re-implemented here with a slightly different approach, and all of the equivalent tests are now passing.

See submodule readme for details.

coords

coords.tilecoords2lnglat

Transform Mapbox's relative tile (x, y) coordinates into longitude/latitude degrees.

distance

distance.haversine

Compute the distance between two points on the globe using the haversine formula.

Rendering

For debugging and general interest, the cover algorithm can be visualized with the scripts/render.py script.

It requires that gdal and ImageMagick are installed. Then, run:

poetry install --with render

An example usage is rendering the degenring test fixture at zooms 1-14. The output will be stored as a GIF in render.gif.

cat tests/fixtures/degenring.geojson | poetry run python scripts/render.py --zmin 1 --zmax 13 --out render.gif

Development

Set up the environment with poetry:

poetry install --with dev
poetry run pre-commit install

Tests

poetry run pytest