Geo Functionsedit

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 and geo_shape fields, or returned by other geo functions.

Limitationsedit

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

  • geo_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 Conversionedit

ST_AsWKTedit

Synopsis: 

ST_AsWKT(
    geometry 
)

Input:

geometry

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 (4.850311987102032 52.347556999884546)

ST_WKTToSQLedit

Synopsis: 

ST_WKTToSQL(
    string 
)

Input:

string WKT representation of geometry

Output: geometry

Description: Returns the geometry from WKT representation.

SELECT city, ST_AsWKT(location) location FROM "geo" WHERE city = 'Amsterdam';

     city:s    |     location:s
Amsterdam      |point (4.850311987102032 52.347556999884546)

Geometry Propertiesedit

ST_GeometryTypeedit

Synopsis: 

ST_GeometryType(
    geometry 
)

Input:

geometry

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_Xedit

Synopsis: 

ST_X(
    geometry 
)

Input:

geometry

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_Yedit

Synopsis: 

ST_Y(
    geometry 
)

Input:

geometry

Output: double

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

SELECT ST_Y(ST_WKTToSQL('POINT (10 20)')) y;

      y:d
20.0

ST_Zedit

Synopsis: 

ST_Z(
    geometry 
)

Input:

geometry

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_Distanceedit

Synopsis: 

ST_Distance(
    geometry, 
    geometry  
)

Input:

source geometry

target geometry

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