earthdistance

Overview

Version

Install

Note: This is a built-in contrib extension of PostgreSQL

CREATE EXTENSION earthdistance;

Usage

earthdistance: Great circle distances on the surface of the Earth

The earthdistance module provides two different approaches to calculating great circle distances on the surface of the Earth. The Earth is assumed to be perfectly spherical (for more accuracy, use PostGIS).

CREATE EXTENSION earthdistance CASCADE; -- requires cube

Cube-Based Earth Distances

Data is stored in cubes using 3 coordinates representing x, y, z distance from Earth’s center. A earth domain over type cube is provided.

Functions

Example

-- Distance between New York and London in meters
SELECT earth_distance(
  ll_to_earth(40.7128, -74.0060),
  ll_to_earth(51.5074, -0.1278)
);

-- Find all points within 1000 meters of a location (indexable)
SELECT *
FROM places
WHERE earth_box(ll_to_earth(40.7128, -74.0060), 1000) @> ll_to_earth(lat, lon);

Point-Based Earth Distances

Represents Earth locations as point type values where the first component is longitude and the second is latitude (in degrees).

Operators

Example

-- Distance in statute miles
SELECT point(-74.0060, 40.7128) <@> point(-0.1278, 51.5074);

Note: Units are hardwired to statute miles. The point-based approach has edge condition issues near poles and ±180° longitude; the cube-based representation avoids these discontinuities.