ST_ToPoint function
The ST_ToPoint function takes a geometry as an input parameter and converts it to a point. The resulting point is represented in the spatial reference system of the given geometry.
The given geometry must be empty or a point. If the given geometry is null, then null is returned.
This function can also be called as a method.
Syntax
Parameter
- geometry
- A value of type ST_Geometry or one of its subtypes that represents
the geometry that is converted to a point.
A geometry can be converted to a point if it is empty or a point. If the conversion cannot be performed, then an exception condition is raised (SQLSTATE 38SUD).
Return type
db2gse.ST_Point
Example
This example creates three geometries
in SAMPLE_GEOMETRIES and converts each to a point.
SET CURRENT FUNCTION PATH = CURRENT FUNCTION PATH, db2gse
CREATE TABLE sample_geometries (id INTEGER, geometry ST_Geometry)
INSERT INTO sample_geometries
VALUES (1, ST_Geometry ('point (30 40)', 1) ),
(2, ST_Geometry ('linestring empty', 1) ),
(3, ST_Geometry ('multipolygon empty', 1) )
In the following SELECT statement, the ST_ToPoint function
is used to return points converted to ST_Point from the static type
of ST_Geometry.
SELECT CAST( ST_AsText( ST_ToPoint(geometry) ) AS VARCHAR(35) ) POINTS
FROM sample_geometries
Results:
POINTS
---------------------------------
POINT ( 30.00000000 40.00000000)
POINT EMPTY
POINT EMPTY