ST_IsRing
ST_IsRing returns true if the input linestring is a ring. A linestring is a ring if it is closed and simple.
Syntax
ST_IsRing(geom)
Arguments
- geom
-
A value of data type
GEOMETRYor an expression that evaluates to aGEOMETRYtype. The geometry must be aLINESTRING.
Return type
BOOLEAN
If geom is not a LINESTRING, then an error is returned.
Examples
The following SQL checks if the specified linestring is a ring.
SELECT ST_IsRing(ST_GeomFromText('linestring(0 0, 1 1, 1 2, 0 0)'));
st_isring
-----------
true
