ST_GeomFromText function

The ST_GeomFromText function takes a well-known text (WKT) format or a GeoJSON format of a geometry and, optionally, a spatial reference system identifier as input parameters and returns the corresponding geometry.

ST_GeomFromText constructs a geometry from one of the following inputs:

A WKT format
GeoJSON format

The preferred version for this functionality is ST_Geometry.

If the specified WKT format is null, then null is returned.

If the specified WKT or GeoJSON format is null, then null is returned.

For details about the supported formats, see Supported data formats.

Syntax

Parameters

wkt

A value of type VARCHAR or CLOB(2G) that contains the WKT format of the resulting geometry.

geojson

A value of type VARCHAR or CLOB(2G) that represents the resulting geometry using GeoJSON.

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 4326 is used implicitly.

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

Return type

ST_Geometry

Example

In the following example, 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, a linestring, and a polygon 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 format.


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(ST_AsText(geometry) AS varchar(105)) 
   AS geometry 
FROM   sample_geometries

Results:


ID    GEOMETRY
----- -----------------------------------------------------------------
 1251 POINT (1.000000 2.000000)                                             
 1252 LINESTRING (33.000000 2.000000, 34.000000 3.000000, 35.000000 6.000000)
 1253 POLYGON ((3.000000 3.000000, 5.000000 3.000000, 4.000000 6.000000, 
                3.000000 3.000000))

Examples

Example 1:

In the following example, 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, a linestring, and a polygon 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 format.


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(ST_AsText(geometry) AS varchar(105)) 
   AS geometry 
FROM   sample_geometries

Results:


ID    GEOMETRY
----- -----------------------------------------------------------------
 1251 POINT (1.000000 2.000000)                                             
 1252 LINESTRING (33.000000 2.000000, 34.000000 3.000000, 35.000000 6.000000)
 1253 POLYGON ((3.000000 3.000000, 5.000000 3.000000, 4.000000 6.000000, 
          3.000000 3.000000))

Example 2:

In the following example, 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, a linestring and a polygon from a GeoJSON point representation using the same values as in Example 1. The following code inserts rows into the SAMPLE_POINTS table with IDs and geometries in the default spatial reference system 4326.


CREATE TABLE sample_geometries(id INTEGER, geometry ST_GEOMETRY)

INSERT INTO sample_geometries(id, geometry)
VALUES
    (1251, ST_GeomFromText('{ "type": "point", "coordinates": [1, 2] }') ),
    (1252, ST_GeomFromText('{ "type": "linestring", "coordinates": [[33, 2], [34, 3], [35, 6]] }') ),
    (1253, ST_GeomFromText('{ "type": "polygon", "coordinates": [[[3, 3], [4, 6], [5, 3], [3, 3]]] }') )

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


SELECT id, cast(ST_AsText(geometry) AS varchar(300)) 
   AS geometry 
FROM   sample_geometries

Results:


ID          GEOMETRY
----------- ---------------------------------------------------------------------------------------------------------
       1251 POINT (1.000000000 2.000000000)
       1252 LINESTRING (33.000000000 2.000000000, 34.000000000 3.000000000, 35.000000000 6.000000000)
       1253 POLYGON ((3.000000000 3.000000000, 5.000000000 3.000000000, 4.000000000 6.000000000, 3.000000000 3.000000000))