Geospatial indexing

Options for indexing geospatial data

Redis supports two different schema types for geospatial data:

• GEO: This uses a simple format where individual geospatial points are specified as numeric longitude-latitude pairs.
• GEOSHAPE: This uses a subset of the Well-Known Text (WKT) format to specify both points and polygons using either geographical coordinates or Cartesian coordinates.

The sections below explain how to index these schema types. See the Geospatial reference page for a full description of both types.

GEO

The following command creates a GEO index for JSON objects that contain the geospatial data in a field called location:

> FT.CREATE productidx ON JSON PREFIX 1 product: SCHEMA $.location AS location GEO
OK

If you now add JSON objects with the product: prefix and a location field, they will be added to the index automatically:

> JSON.SET product:46885 $ '{"description": "Navy Blue Slippers","price": 45.99,"city": "Denver","location": "-104.991531, 39.742043"}'
OK
> JSON.SET product:46886 $ '{"description": "Bright Green Socks","price": 25.50,"city": "Fort Collins","location": "-105.0618814,40.5150098"}'
OK

The query below finds products within a 100 mile radius of Colorado Springs (Longitude=-104.800644, Latitude=38.846127). This returns only the location in Denver, but a radius of 200 miles would also include the location in Fort Collins:

> FT.SEARCH productidx '@location:[-104.800644 38.846127 100 mi]'
1) "1"
2) "product:46885"
3) 1) "$"
   2) "{\"description\":\"Navy Blue Slippers\",\"price\":45.99,\"city\":\"Denver\",\"location\":\"-104.991531, 39.742043\"}"

See Geospatial queries for more information about the available options.

GEOSHAPE

The following command creates an index for JSON objects that include geospatial data in a field called geom. The FLAT option at the end of the field definition specifies Cartesian coordinates instead of the default spherical geographical coordinates. Use SPHERICAL in place of FLAT to choose the coordinate space explicitly.

> FT.CREATE geomidx ON JSON PREFIX 1 shape: SCHEMA $.name AS name TEXT $.geom AS geom GEOSHAPE FLAT
OK

Use the shape: prefix for the JSON objects to add them to the index:

> JSON.SET shape:1 $ '{"name": "Green Square", "geom": "POLYGON ((1 1, 1 3, 3 3, 3 1, 1 1))"}'
OK
> JSON.SET shape:2 $ '{"name": "Red Rectangle", "geom": "POLYGON ((2 2.5, 2 3.5, 3.5 3.5, 3.5 2.5, 2 2.5))"}'
OK
> JSON.SET shape:3 $ '{"name": "Blue Triangle", "geom": "POLYGON ((3.5 1, 3.75 2, 4 1, 3.5 1))"}'
OK
> JSON.SET shape:4 $ '{"name": "Purple Point", "geom": "POINT (2 2)"}'
OK

You can now run various geospatial queries against the index. For example, the query below returns any shapes within the boundary of the green square but omits the green square itself:

> FT.SEARCH geomidx "(-@name:(Green Square) @geom:[WITHIN $qshape])" PARAMS 2 qshape "POLYGON ((1 1, 1 3, 3 3, 3 1, 1 1))" RETURN 1 name DIALECT 4

1) (integer) 1
2) "shape:4"
3) 1) "name"
   2) "[\"Purple Point\"]"

You can also run queries to find whether shapes in the index completely contain or overlap each other. See Geospatial queries for more information.