ST_MLineFromText function

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

ST_MLineFromText constructs a geometry from one of the following inputs:

A WKT format
GeoJSON format

The recommended function for achieving the same result is the ST_MultiLineString function. It is recommended because of its flexibility: ST_MultiLineString takes additional forms of input as well as the WKT or GeoJSON formats.

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 multilinestring.

geojson

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

srs_id

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

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

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

Return type

ST_MultiLineString

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.

This example illustrates how ST_MLineFromText can be used to create and insert a multilinestring from its WKT format. The record that is inserted has ID = 1110, and the geometry is a multilinestring in spatial reference system 1. The multilinestring is in the well-known text representation of a multilinestring. The X and Y coordinates for this geometry are:

Line 1: (33, 2) (34, 3) (35, 6)
Line 2: (28, 4) (29, 5) (31, 8) (43, 12)
Line 3: (39, 3) (37, 4) (36, 7)


CREATE TABLE sample_mlines (id INTEGER, geometry ST_MultiLineString)

INSERT INTO sample_mlines
  VALUES (1110, ST_MLineFromText ('multilinestring ( (33 2, 34 3, 35 6),
                                                     (28 4, 29 5, 31 8, 43 12),
                                                     (39 3, 37 4, 36 7) )', 1) )

The following SELECT statement returns the multilinestring that was recorded in the table:


SELECT id, CAST( ST_AsText( geometry ) AS VARCHAR(280) ) MULTI_LINE_STRING
  FROM sample_mlines
  WHERE id = 1110

Results:


ID   MULTI_LINE_STRING
---- ------------------------------------------------------------------------------
1110 MULTILINESTRING ((33.000000 2.000000, 34.000000 3.000000, 35.000000 6.000000),
                      (28.000000 4.000000, 29.000000 5.000000, 31.000000 8.000000, 
                       43.000000 12.000000),
                      (39.000000 3.000000, 37.000000 4.000000, 36.000000 7.000000))

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.

Line 1: (33, 2) (34, 3) (35, 6)
Line 2: (28, 4) (29, 5) (31, 8) (43, 12)
Line 3: (39, 3) (37, 4) (36, 7)


CREATE TABLE sample_mlines (id INTEGER, geometry ST_MultiLineString)

INSERT INTO sample_mlines
  VALUES (1110, ST_MLineFromText ('multilinestring ( (33 2, 34 3, 35 6),
                                                     (28 4, 29 5, 31 8, 43 12),
                                                     (39 3, 37 4, 36 7) )', 1) )

The following SELECT statement returns the multilinestring that was recorded in the table:


SELECT id, CAST( ST_AsText( geometry ) AS VARCHAR(280) ) MULTI_LINE_STRING
  FROM sample_mlines
  WHERE id = 1110

Results:


ID   MULTI_LINE_STRING
---- ------------------------------------------------------------------------------
1110 MULTILINESTRING ((33.000000 2.000000, 34.000000 3.000000, 35.000000 6.000000),
                      (28.000000 4.000000, 29.000000 5.000000, 31.000000 8.000000, 
                       43.000000 12.000000),
                      (39.000000 3.000000, 37.000000 4.000000, 36.000000 7.000000))

Example 2:

This example illustrates how ST_MLineFromText can be used to create and insert a multilinestring from its GeoJSON format using the same geometry data from Example 1. The record that is inserted has ID = 1111, and the geometry is a multilinestring in spatial reference system 4326 (the default).


CREATE TABLE sample_mlines (id INTEGER, geometry ST_MultiLineString)

INSERT INTO sample_mlines
  VALUES (1111, ST_MLineFromText ('{ "type": "multilinestring", "coordinates": 
                                   [ [[33, 2], [34, 3], [35, 6]],
                                     [[28, 4], [29, 5], [31, 8], [43, 12]],
                                     [[39, 3], [37, 4], [36, 7]] 
                                   ] }') )

The following SELECT statement returns the multilinestring that was recorded in the table:


SELECT id, CAST( ST_AsText( geometry ) AS VARCHAR(350) ) MULTI_LINE_STRING
  FROM sample_mlines
  WHERE id = 1111

Results:


ID          MULTI_LINE_STRING
----------- -------------------------------------------------------------------------
1111        MULTILINESTRING ((33.000000000 2.000000000, 34.000000000 3.000000000, 
                              35.000000000 6.000000000),(28.000000000 4.000000000, 
                              29.000000000 5.000000000, 31.000000000 8.000000000, 
                              43.000000000 12.000000000),(39.000000000 3.000000000, 
                              37.000000000 4.000000000, 36.000000000 7.000000000))