ST_GeomFromText function

The ST_GeomFromText function takes a well-known text representation of a geometry and, optionally, a spatial reference system identifier as input parameters and returns the corresponding geometry.

If the given well-known text representation is null, then null is returned.

The preferred version for this functionality is ST_Geometry.

Syntax

Parameter

wkt

A value of type CLOB(2G) that contains the well-known text representation of the resulting geometry.

srs_id

A value of type INTEGER that identifies the spatial reference system for the resulting geometry.

If the srs_id parameter is omitted, the spatial reference system with the numeric identifier 0 (zero) is used implicitly.

If srs_id does not identify a spatial reference system listed in the catalog view DB2GSE.ST_SPATIAL_REFERENCE_SYSTEMS, then an error is returned (SQLSTATE 38SU1).

Return type

db2gse.ST_Geometry

Example

In the following examples, the lines of results have been reformatted for readability. The spacing in your results will vary according to your online display.

In this example the ST_GeomFromText function is used to create and insert a point from a well known text (WKT) point representation.

The following code inserts rows into the SAMPLE_POINTS table with IDs and geometries in spatial reference system 1 using WKT representation.


SET CURRENT FUNCTION PATH = CURRENT FUNCTION PATH, db2gse 

CREATE TABLE sample_geometries(id INTEGER, geometry ST_GEOMETRY)

INSERT INTO sample_geometries(id, geometry)
VALUES
    (1251, ST_GeomFromText('point(1 2)', 1) ),
    (1252, ST_GeomFromText('linestring(33 2, 34 3, 35 6)', 1) ),
    (1253, ST_GeomFromText('polygon((3 3, 4 6, 5 3, 3 3))', 1))

The following SELECT statement will return the ID and GEOMETRIES from the SAMPLE_GEOMETRIES table.


SELECT id, cast(geometry..ST_AsText AS varchar(105)) 
   AS geometry 
FROM   sample_geometries

Results:


ID          GEOMETRY
----------- ---------------------------------------------------------------
       1251 POINT ( 1.00000000 2.00000000)
                                          
       1252 LINESTRING ( 33.00000000 2.00000000, 34.00000000 3.00000000, 
              35.00000000 6.00000000)

       1253 POLYGON (( 3.00000000 3.00000000, 5.00000000 3.00000000, 
              4.00000000 6.00000000, 3.00000000 3.00000000))