ST_Boundary

Determine the boundary of a geometry. ST_Boundary takes a geometry and returns its combined boundary as a geometry.

Syntax

ST_Boundary(geo);

geo: The input geometry.
Type: VARCHAR(ANY)

Returns

A value of type VARCHAR(ANY) that contains a geometry.

Examples

inza..ST_AsText(inza..ST_Boundary(inza..ST_WKTToSQL('POLYGON ((1 1, 1 2, 2 2, 2 1, 1
            1))')));

ST_ASTEXT
-----------
LINESTRING (1 1, 1 2, 2 2, 2 1, 1 1)
(1 row)

inza..ST_AsText(inza..ST_Boundary(inza..ST_WKTToSQL('LINESTRING (0 0, 1 1, 2 2)')));

ST_ASTEXT
-----------
MULTIPOINT (0 0, 2 2)
(1 row)