ST_LineString function

The ST_LineString function constructs a linestring from specified input.

The inputs can be specified in one of the following formats:

Well-known text (WKT) format
Well-known binary (WKB) format
ESRI shape format
GeoJSON format
Geography Markup Language (GML) format

A spatial reference system identifier can be provided optionally to identify the spatial reference system that the resulting linestring is in.

If the specified 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 linestring.

wkb

A value of type VARBINARY or BLOB(2G) that contains the WKB format of the resulting linestring.

shape

A value of type VARBiNARY or BLOB(2G) that represents the ESRI shape format of the resulting linestring.

geojson

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

gml

A value of type VARCHAR or CLOB(2G) that represents the resulting linestring using the Geography Markup Language (GML).

srs_id

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

If the srs_id parameter is omitted, then the spatial reference system with the numeric identifier 4326 is used.

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_LineString

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.

The following code uses the ST_LineString function to create and insert a line from a well-known text (WKT) line representation or from a well-known binary (WKB) format.The following code uses the ST_LineString function to create and insert a line from a well-known text (WKT) line representation, a geographic markup language (GML), or a GeoJSON format.

The following example inserts a row into the SAMPLE_LINES table with an ID and line in spatial reference system 1 in WKT and GML format.The following example inserts a row into the SAMPLE_LINES table with an ID and line in the default spatial reference system 4326 in WKT, GML format, and GeoJSON format.

 
CREATE TABLE sample_lines(id SMALLINT, geometry ST_LineString)
 
INSERT INTO sample_lines(id, geometry)
VALUES
    (1110, ST_LineString('linestring(850 250, 850 850)', 1)),
    (1111, ST_LineString('<gml:LineString srsName="EPSG:4269"><gml:coord>
                          <gml:X>90</gml:X><gml:Y>90</gml:Y>
                          </gml:coord><gml:coord><gml:X>100</gml:X>
                          <gml:Y>100</gml:Y></gml:coord>
                          </gml:LineString>', 1))

SELECT id, cast(ST_AsText(geometry) AS varchar(75)) AS linestring
FROM   sample_lines

 
CREATE TABLE sample_lines(id SMALLINT, geometry ST_LineString)
 
INSERT INTO sample_lines(id, geometry)
VALUES
    (1110, ST_LineString('linestring(850 250, 850 850)')),
    (1111, ST_LineString('<gml:LineString srsName="EPSG:4326"><gml:coord>
                          <gml:X>90</gml:X><gml:Y>90</gml:Y>
                          </gml:coord><gml:coord><gml:X>100</gml:X>
                          <gml:Y>100</gml:Y></gml:coord>
                          </gml:LineString>')),
    (1112, ST_LineString('{ "type": "Linestring", "coordinates": 
                          [[10.0, 11.2], [10.5, 11.9]] }'))

SELECT id, cast(ST_AsText(geometry) AS varchar(75)) AS linestring
FROM   sample_lines

Results:


ID     LINESTRING
------ ------------------------------------------------------------------
  1110 LINESTRING (850.000000 250.000000, 850.000000 850.000000)
  1111 LINESTRING (90.000000 90.000000, 100.000000 100.000000)


ID     LINESTRING
------ ------------------------------------------------------------------
  1110 LINESTRING (850.000000 250.000000, 850.000000 850.000000)
  1111 LINESTRING (90.000000 90.000000, 100.000000 100.000000)
  1112 LINESTRING (10.000000000 11.200000000, 10.500000000 11.900000000)