Mastering Redis GEO: Add Locations, Radius Searches, and Distance Calculations

Redis has just released version 3.2 , officially supporting geographic GEO APIs. These commands are ideal for simple location‑based services such as finding nearby merchants or calculating distances between users and stores.

Usage Example

GEOADD locations -0.12455 51.5007 "Big Ben" -0.12520 51.50115 "Westminster Station" -0.11358 51.50482 "BFI IMAX"

The command returns (integer) 3, indicating three location entries were added. Each entry consists of latitude, longitude, and a name.

Radius Search

To find merchants within 500 meters of a user at -0.11759 51.50574: GEORADIUS locations -0.11759 51.50574 500 m Result: "BFI IMAX".

To also return distances and sort by proximity: GEORADIUS locations -0.11759 51.50574 1 km WITHDIST ASC Result includes members with their distances, e.g., "BFI IMAX" – 0.2960 km, "Westminster Station" – 0.7335 km, "Big Ben" – 0.7392 km.

Member‑Based Search

Find locations near a specific member (e.g., "Westminster Station") within 100 m:

GEORADIUSBYMEMBER locations "Westminster Station" 100 m WITHDIST

Returns the member itself with distance 0.0000 and nearby "Big Ben" at 67.3659 m.

Distance Between Members

GEODIST locations "Westminster Station" "BFI IMAX"

Result: "902.1221" meters.

Listing and Removing Members

All stored members can be listed with: ZRANGE locations 0 -1 Result: "Big Ben", "Westminster Station", "BFI IMAX".

Redis stores GEO data in a sorted set (zset); each name becomes a member, and latitude/longitude are converted to a geohash used as the score.

To delete a location: ZREM locations "Big Ben" Result: (integer) 1.

While Redis 3.2 offers a simple and efficient GIS solution for "what's nearby" queries, more comprehensive GIS requirements are better served by PostgreSQL with PostGIS.