ST_IsClosed - Amazon Redshift
SyntaxArgumentsReturn typeExamples

ST_IsClosed

ST_IsClosed returns true if the 2D projection of the input geometry is closed. The following rules define a closed geometry:

  • The input geometry is a point or a multipoint.

  • The input geometry is a linestring, and the start and end points of the linestring coincide.

  • The input geometry is a nonempty multilinestring and all its linestrings are closed.

  • The input geometry is a nonempty polygon, all polygon's rings are nonempty, and the start and end points of all its rings coincide.

  • The input geometry is a nonempty multipolygon and all its polygons are closed.

  • The input geometry is a nonempty geometry collection and all its components are closed.

Syntax

ST_IsClosed(geom)

Arguments

geom

A value of data type GEOMETRY or an expression that evaluates to a GEOMETRY type.

Return type

BOOLEAN

If geom is an empty point, then false is returned.

If geom is null, then null is returned.

Examples

The following SQL checks if the polygon is closed. 

SELECT ST_IsClosed(ST_GeomFromText('POLYGON((0 2,1 1,0 -1,0 2))'));

st_isclosed
-----------
 true