ST_IsRing
Returns TRUE if this
LINESTRING is both closed and simple.
boolean ST_IsRing
geometry g
Description
Returns TRUE if this
LINESTRING is both
(ST_StartPoint(g)
~=
ST_Endpoint(g)) and (does not self intersect).
This method implements the OpenGIS Simple Features
Implementation Specification for SQL. OGC SFSQL 1.1 -
2.1.5.1
This method implements the SQL/MM specification:
SQL-MM 3: 7.1.6
SQL-MM defines the result of
ST_IsRing(NULL) to be 0, while
PostGIS returns NULL.
This function supports 3d and will not drop the z-index.
Examples
See Also
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