polygon-geohasher

Polygon Geohasher is an open source Python package for converting Shapely's polygons into a set of geohashes. It obtains the set of geohashes inside a polygon or geohashes that touch (intersect) the polygon. This library uses python-geohash and shapely.

Requirements

Polygon Geohasher requires:

• Python >= 3.x.
• GEOS >= 3.3 (due to shapely).

Installing

Linux users can get Polygon Geohasher from the Python Package Index with pip (8+):

$ pip install polygon-geohasher

Usage

Here are some simple examples:

from polygon_geohasher import polygon_to_geohashes, geohashes_to_polygon
from shapely import geometry

polygon = geometry.Polygon([(-99.1795917, 19.432134), (-99.1656847, 19.429034),
                            (-99.1776492, 19.414236), (-99.1795917, 19.432134)])
inner_geohashes_polygon = geohashes_to_polygon(polygon_to_geohashes(polygon, 7))
outer_geohashes_polygon = geohashes_to_polygon(polygon_to_geohashes(polygon, 7, False))

Benchmarking

Compare the optimized implementation against the legacy algorithm:

$ .venv/bin/python benchmarks/polygon_to_geohashes.py --iterations 5 --precision 7

Use --inner or --outer to focus on a single mode, and --no-validate to skip output validation.

geohash_to_polygon(geohash):

This function receives a geohash and returns a Shapely's Polygon.

geohashes_to_polygon(geohashes):

This function receives a set of geohashes and returns a Shapely's Polygon or MultiPolygon.

polygon_to_geohashes(polygon, precision[, inner=True]):

This function receives a Shapely's Polygon and the precision of geohashes to be used to create a polygon and returns a set of geohashes (strings) that covers said polygon. It also receives an optional parameter inner that defines the way in which those polygons will be created. If an inner parameter is given, then only contained geohashes will be used; otherwise, intersected geohashes will be used.

See geohashed polygons resulting from both options (with and without inner) in the following example: