This topic describes the ST_Polygon function. This function constructs a polygon object by using a LineString object and a spatial reference identifier (SRID).
Syntax
geometry ST_Polygon(geometry aLineString , integer srid);
Parameters
Parameter | Description |
---|---|
aLineString | The LineString object that you want to specify. |
srid | The spatial reference identifier (SRID) of the polygon object. |
Description
- This function does not support MultiLineString objects. If you want to construct a polygon object by using a MultiLineString object, you can use the ST_LineMerge function to merge the LineString objects that comprise the MultiLineString object.
- This function cannot construct a polygon object that contains holes. If you want to construct a polygon object that contains holes, use the ST_MakePolygon function.
- This function supports 3D objects and does not discard the z-index of the geometry object that is constructed.
Examples
SELECT ST_AsEWKT(ST_Polygon(ST_GeomFromText('LINESTRING(1 2,3 4,5 6,1 2)'),4326));
st_asewkt
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SRID=4326;POLYGON((1 2,3 4,5 6,1 2))
(1 row)