MULTILINESTRING

Warning:
Cockroach Labs will stop providing Assistance Support for this version on May 10, 2022. Prior to that date, upgrade to a more recent version to continue receiving support. For more details, see the Release Support Policy.

A MULTILINESTRING is a collection of LineStrings. MultiLineStrings are useful for gathering a group of LineStrings into one geometry. For example, you may want to gather the LineStrings denoting all of the roads in a particular municipality.

Examples

Well known text

A MultiLineString can be created from SQL by calling the st_geomfromtext function on a MultiLineString definition expressed in the Well Known Text (WKT) format.

icon/buttons/copy
SELECT ST_GeomFromText('MULTILINESTRING((0 0, 1440 900), (800 600, 200 400))');
                                                                                     st_geomfromtext
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  0105000000020000000102000000020000000000000000000000000000000000000000000000008096400000000000208C4001020000000200000000000000000089400000000000C0824000000000000069400000000000007940
(1 row)

SQL

A MultiLineString can be created from SQL by calling an aggregate function such as ST_Collect or ST_Union on a column that contains LineString geometries. In the example below, we will build a MultiLineString from several LineStrings.

First, insert the LineStrings:

icon/buttons/copy
CREATE TABLE tmp_linestrings (id INT8 default unique_rowid(), geom GEOMETRY);

INSERT INTO tmp_linestrings (geom)
VALUES
(st_geomfromtext('SRID=4326;LINESTRING(-88.243385 40.116421, -87.906471 43.038902, -95.992775 36.153980)')),
(st_geomfromtext('SRID=4326;LINESTRING(-75.704722 36.076944, -95.992775 36.153980, -87.906471 43.038902)')),
(st_geomfromtext('SRID=4326;LINESTRING(-76.8261 42.1727,  -75.6608 41.4102,-73.5422 41.052, -73.929 41.707,  -76.8261 42.1727)'));

Next, build a MultiLineString from the individual LineStrings using ST_Collect, and check the output with ST_GeometryType to verify that it is indeed a MultiLineString:

icon/buttons/copy
SELECT ST_GeometryType(st_collect(geom)) AS output FROM tmp_linestrings;
        output
----------------------
  ST_MultiLineString
(1 row)

Finally, drop the temporary table:

icon/buttons/copy
DROP TABLE tmp_linestrings;

See also

YesYes NoNo