Spherical mercator tile and coordinate utilities




Spherical mercator coordinate and tile utilities

The mercantile module provides ul(xtile, ytile, zoom) and bounds(xtile, ytile, zoom) functions that respectively return the upper left corner and bounding longitudes and latitudes for XYZ tiles, a xy(lng, lat) function that returns spherical mercator x and y coordinates, a tile(lng, lat, zoom) function that returns the tile containing a given point, and quadkey conversion functions quadkey(xtile, ytile, zoom) and quadkey_to_tile(quadkey) for translating between quadkey and tile coordinates.

>>> import mercantile
>>> mercantile.ul(486, 332, 10)
LngLat(lng=-9.140625, lat=53.33087298301705)
>>> mercantile.bounds(486, 332, 10)
LngLatBbox(west=-9.140625, south=53.12040528310657, east=-8.7890625, north=53.33087298301705)
>>> mercantile.xy(*mercantile.ul(486, 332, 10))
(-1017529.7205322663, 7044436.526761846)
>>> mercantile.tile(*mercantile.ul(486, 332, 10) + (10,))
Tile(x=486, y=332, z=10)
>>> mercantile.quadkey(486, 332, 10)
>>> mercantile.quadkey_to_tile('0313102310')
Tile(x=486, y=332, z=10)

Also in mercantile are functions to traverse the tile stack.

>>> mercantile.parent(486, 332, 10)
Tile(x=243, y=166, z=9)
>>> mercantile.children(mercantile.parent(486, 332, 10))
[Tile(x=486, y=332, z=10), Tile(x=487, y=332, z=10), Tile(x=487, y=333, z=10), Tile(x=486, y=333, z=10)]

Named tuples are used to represent tiles, coordinates, and bounding boxes.

Mercantile CLI

Mercantile's command line interface, named "mercantile", has commands for getting the shapes of Web Mercator tiles as GeoJSON and getting the tiles that intersect with a GeoJSON bounding box.

$ mercantile
Usage: mercantile [OPTIONS] COMMAND [ARGS]...

  Command line interface for the Mercantile Python package.

  -v, --verbose  Increase verbosity.
  -q, --quiet    Decrease verbosity.
  --help         Show this message and exit.

  children  Write the children of the tile.
  parent    Write the parent tile.
  quadkey   Convert to/from quadkeys.
  shapes    Write the shapes of tiles as GeoJSON.
  tiles     List tiles that overlap or contain a lng/lat point, bounding box,
            or GeoJSON objects.

See docs/cli.rst for more about the mercantile program.

See Also

node-sphericalmercator provides many of the same features for Node.

tilebelt has some of the GeoJSON features as mercantile and a few more (tile parents, quadkey).