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ST_Perimeter

Signature

DOUBLE ST_Perimeter(GEOMETRY poly);

Description

Returns the perimeter of a polygon or a multipolygon.

Note that (multi)polygons within geometrycollection are accepted.

Perimeter is measured in the units of the spatial reference system.

Implements the OpenGIS Simple Features Implementation Specification for SQL version 1.2.1.

Examples

SELECT ST_Perimeter('POLYGON((1 2, 4 2, 4 6, 1 6, 1 2))');
-- Answer: 14.0

SELECT ST_Perimeter('MULTIPOLYGON(((0 2, 3 2, 3 6, 0 6, 0 2)),
                                  ((5 0, 7 0, 7 1, 5 1, 5 0)))');
-- Answer: 20.0

SELECT ST_Perimeter('GEOMETRYCOLLECTION(
                    MULTIPOINT((4 4), (1 1), (1 0), (0 3)),
                    LINESTRING(2 1, 1 3, 5 2),
                    POLYGON((1 2, 4 2, 4 6, 1 6, 1 2)))');
-- Answer: 14.0

SELECT ST_Perimeter('LINESTRING(2 1, 1 3, 5 2)');
-- Answer: 0
See also