Decoding Mapbox Vector Tiles?

Question

I'm using the Mapbox Vector Tile API and I want to get the data into one or multiple GeoPandas GeoDataFrame. (Python)

After I download the .mvt file, how do I decode it?

What I've tried already:

• mapbox-vector-tile library, this decodes the file into a dictionary (JSON) but does not transform the given coordinates.
• python-vt2geojson library, this transforms the coordinates but the information about the layers is lost.
• ogr2ogr with ogr2ogr -f GeoJSON $file_path_json $file_path_mvt -oo x=$x -oo y=$y -oo z=$z but this yields the error

ERROR 1: Layer 'aeroway' does not already exist in the output dataset, and cannot be created by the output driver.
ERROR 1: Terminating translation prematurely after failed
translation of layer aeroway (use -skipfailures to skip errors)

• ogr2ogr with ogr2ogr -f "ESRI Shapefile" $file_path_shp $file_path_mvt -oo x=$x -oo y=$y -oo z=$z but this yields the error

Warning 6: Normalized/laundered field name: 'admin_level' to 'admin_leve'
Warning 6: Normalized/laundered field name: 'name_script' to 'name_scrip'
Warning 6: Normalized/laundered field name: 'text_anchor' to 'text_ancho'
Warning 6: Normalized/laundered field name: 'name_zh-Hans' to 'name_zh-Ha'
Warning 6: Normalized/laundered field name: 'name_script' to 'name_scrip'
Warning 6: Normalized/laundered field name: 'name_zh-Hant' to 'name_zh-_1'
Warning 1: One or several characters couldn't be converted correctly from UTF-8 to ISO-8859-1.  This warning will not be emitted anymore.
Warning 6: Normalized/laundered field name: 'name_script' to 'name_scrip'
Warning 6: Normalized/laundered field name: 'shield_text_color' to 'shield_tex'
ERROR 1: Attempt to write non-linestring (GEOMETRYCOLLECTION) geometry to ARC type shapefile.
ERROR 1: Unable to write feature 91 from layer road.
ERROR 1: Terminating translation prematurely after failed
translation of layer road (use -skipfailures to skip errors)

Has anyone a clue of how to decode Mapbox Vector Tile files into files that can be read into GeoPandas with the coordinates transformed to longitude and latitude?

Answer 1

According to https://github.com/OSGeo/gdal/issues/801#issuecomment-408111458, GDAL only supports one layer per file. Thus, you need to append layer name after your GDAL command.

For example, ogr2ogr -f GeoJSON $file_path_json $file_path_mvt -oo x=$x -oo y=$y -oo z=$z aeroway will generate a geojson file for the aeroway layer.

Answer 2

Using the mapbox-vector-tile library you can convert back to WGS84 decimal degrees if you know the zoom, column (tile_x), and row (tile_y) of the tile. E.g.:

import mapbox_vector_tile
import math

def pixel2deg(xtile, ytile, zoom, xpixel, ypixel, extent = 4096):
  n = 2.0 ** zoom
  xtile = xtile + (xpixel / extent)
  ytile = ytile + ((extent - ypixel) / extent)
  lon_deg = (xtile / n) * 360.0 - 180.0
  lat_rad = math.atan(math.sinh(math.pi * (1 - 2 * ytile / n)))
  lat_deg = math.degrees(lat_rad)
  return (lon_deg, lat_deg)

mapbox_vector_tile.decode(your_mvt, 
  transformer = lambda x, y: pixel2deg(tile_x, tile_y, tile_zoom, x, y)
)