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Geo functions

Warning

This functionality is in beta and is subject to change. The design and code is less mature than official GA features and is being provided as-is with no warranties. Beta features are not subject to the support SLA of official GA features.

The geo functions work with geometries stored in geo_point, geo_shape and shape fields, or returned by other geo functions.

Limitations

geo_point, geo_shape and shape and types are represented in SQL as geometry and can be used interchangeably with the following exceptions:

  • geo_shape and shape fields don’t have doc values, therefore these fields cannot be used for filtering, grouping or sorting.
  • geo_points fields are indexed and have doc values by default, however only latitude and longitude are stored and indexed with some loss of precision from the original values (4.190951585769653E-8 for the latitude and 8.381903171539307E-8 for longitude). The altitude component is accepted but not stored in doc values nor indexed. Therefore calling ST_Z function in the filtering, grouping or sorting will return null.

Geometry Conversion

ST_AsWKT( geometry )

Input:

  1. geometry. If null, the function returns null.

Output: string

Description: Returns the WKT representation of the geometry.

SELECT city, ST_AsWKT(location) location FROM "geo" WHERE city = 'Amsterdam'; city:s | location:s Amsterdam |POINT (4.850312 52.347557) 
ST_WKTToSQL( string )

Input:

  1. string WKT representation of geometry. If null, the function returns null.

Output: geometry

Description: Returns the geometry from WKT representation.

SELECT CAST(ST_WKTToSQL('POINT (10 20)') AS STRING) location; location:s POINT (10.0 20.0)

Geometry Properties

ST_GeometryType( geometry )

Input:

  1. geometry. If null, the function returns null.

Output: string

Description: Returns the type of the geometry such as POINT, MULTIPOINT, LINESTRING, MULTILINESTRING, POLYGON, MULTIPOLYGON, GEOMETRYCOLLECTION, ENVELOPE or CIRCLE.

SELECT ST_GeometryType(ST_WKTToSQL('POINT (10 20)')) type; type:s POINT 
ST_X( geometry )

Input:

  1. geometry. If null, the function returns null.

Output: double

Description: Returns the longitude of the first point in the geometry.

SELECT ST_X(ST_WKTToSQL('POINT (10 20)')) x; x:d 10.0 
ST_Y( geometry )

Input:

  1. geometry. If null, the function returns null.

Output: double

Description: Returns the latitude of the first point in the geometry.

SELECT ST_Y(ST_WKTToSQL('POINT (10 20)')) y; y:d 20.0 
ST_Z( geometry )

Input:

  1. geometry. If null, the function returns null.

Output: double

Description: Returns the altitude of the first point in the geometry.

SELECT ST_Z(ST_WKTToSQL('POINT (10 20 30)')) z; z:d 30.0 
ST_Distance( geometry, geometry )

Input:

  1. source geometry. If null, the function returns null.
  2. target geometry. If null, the function returns null.

Output: Double

Description: Returns the distance between geometries in meters. Both geometries have to be points.

SELECT ST_Distance(ST_WKTToSQL('POINT (10 20)'), ST_WKTToSQL('POINT (20 30)')) distance; distance:d 1499101.2889383635