earthdistance

Extensions

earthdistance

earthdistance : calculate great-circle distances on the surface of the Earth

Overview

ID	Extension	Package	Version	Category	License	Language
1690	earthdistance	earthdistance	`1.2`	GIS	PostgreSQL	C

Attribute	Has Binary	Has Library	Need Load	Has DDL	Relocatable	Trusted
--s-d--	No	Yes	No	Yes	no	no

Relationships
Requires	cube
See Also	postgis q3c pg_sphere postgis_topology postgis_raster postgis_sfcgal postgis_tiger_geocoder address_standardizer

Packages

PG18	PG17	PG16	PG15	PG14
1.2	1.2	1.2	1.2	1.2

This is a built-in contrib extension ship with the PostgreSQL kernel

Install

Create this extension with:

CREATE EXTENSION earthdistance CASCADE; -- requires cube

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

Function	Description
`earth()` → `float8`	Returns the assumed radius of the Earth
`sec_to_gc(float8)` → `float8`	Converts straight line (secant) distance to great circle distance
`gc_to_sec(float8)` → `float8`	Converts great circle distance to straight line (secant) distance
`ll_to_earth(float8, float8)` → `earth`	Returns location given latitude and longitude in degrees
`latitude(earth)` → `float8`	Returns latitude in degrees
`longitude(earth)` → `float8`	Returns longitude in degrees
`earth_distance(earth, earth)` → `float8`	Returns great circle distance between two points
`earth_box(earth, float8)` → `cube`	Returns a box for indexed search using cube `@>` operator

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

Operator	Description
`point <@> point` → `float8`	Distance in statute miles between two points

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.

Last updated on 2026-03-24

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