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ST_Polygon

PDFRSS

ST_Polygon returns a polygon geometry whose outer ring is the input linestring with the value that was input for the spatial reference system identifier (SRID).

The dimension of the returned geometry is the same as that of the input geometry.

Syntax

ST_Polygon(linestring, srid)

Arguments

linestring

A value of data type GEOMETRY or an expression that evaluates to a GEOMETRY type. The subtype must be LINESTRING that represents a linestring. The linestring value must be closed.

srid

A value of data type INTEGER that represents a SRID.

Return type

GEOMETRY of subtype POLYGON.

The SRID value of the returned geometry is set to srid.

If linestring or srid is null, then null is returned.

If linestring is not a linestring, then an error is returned.

If linestring is not closed, then an error is returned.

If srid is negative, then an error is returned.

Examples

The following SQL constructs a polygon with an SRID value.

SELECT ST_AsEWKT(ST_Polygon(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 29.31,77.29 29.07)'),4356));

st_asewkt
-------------
 SRID=4356;POLYGON((77.29 29.07,77.42 29.26,77.27 29.31,77.29 29.07))