pg_geohash

Overview

Version

Build

You can build the RPM / DEB packages for pg_geohash using pig build:

pig build pkg pg_geohash         # build RPM / DEB packages

Install

You can install pg_geohash directly. First, make sure the PGDG and PIGSTY repositories are added and enabled:

pig repo add pgsql -u          # Add repo and update cache

Install the extension using pig or apt/yum/dnf:

• Install
• pig
• dnf
• apt

pig install pg_geohash;          # Install for current active PG version

pig ext install -y pg_geohash -v 18  # PG 18
pig ext install -y pg_geohash -v 17  # PG 17
pig ext install -y pg_geohash -v 16  # PG 16
pig ext install -y pg_geohash -v 15  # PG 15
pig ext install -y pg_geohash -v 14  # PG 14

dnf install -y pg_geohash_18       # PG 18
dnf install -y pg_geohash_17       # PG 17
dnf install -y pg_geohash_16       # PG 16
dnf install -y pg_geohash_15       # PG 15
dnf install -y pg_geohash_14       # PG 14

apt install -y postgresql-18-pg-geohash   # PG 18
apt install -y postgresql-17-pg-geohash   # PG 17
apt install -y postgresql-16-pg-geohash   # PG 16
apt install -y postgresql-15-pg-geohash   # PG 15
apt install -y postgresql-14-pg-geohash   # PG 14

Create Extension:

CREATE EXTENSION pg_geohash;

Usage

pg_geohash: Geohash functions for PostgreSQL

C-based geohash functions for PostgreSQL (also supports HAWQ and Greenplum). Based on the libgeohash C library.

Background on geohash: Wikipedia: Geohash

Functions

Encode latitude/longitude to a geohash string with specified precision:

SELECT LAT_LON_TO_GEOHASH_WITH_LEN(latitude, longitude, 5) AS geohash;

Encode latitude/longitude to a full-precision geohash:

SELECT LAT_LON_TO_GEOHASH(latitude, longitude) AS geohash;

Decode a geohash back to latitude/longitude:

SELECT GEOHASH_TO_LAT_LON('dp3w7') AS lat_lon;

Example

Compute geohash-based aggregates using 5-character precision (~2.4km x 4.9km cells):

SELECT LAT_LON_TO_GEOHASH_WITH_LEN(latitude, longitude, 5) AS geohash,
       COUNT(*)
FROM crimes
GROUP BY 1
ORDER BY 2 DESC
LIMIT 10;

 geohash | count
---------+-------
 dp3w7   | 72404
 dp3tt   | 70713
 dp3tw   | 63642
 dp3wm   | 62332
 dp3wk   | 56467

Recover coordinates from a geohash:

SELECT location,
       GEOHASH_TO_LAT_LON(LAT_LON_TO_GEOHASH(latitude, longitude))
FROM crimes
LIMIT 5;