PostGIS
Description
Returns TRUE if this LINESTRING is both
ST_IsClosed (ST_StartPoint(`g)`
~= ST_Endpoint(`g)`) and
ST_IsSimple (does not self intersect).
[.inlinemediaobject]
This method implements the
OGC Simple Features
Implementation Specification for SQL 1.1.
2.1.5.1
This
method implements the SQL/MM specification.
SQL-MM 3: 7.1.6
|
Examples
SELECT ST_IsRing(geom), ST_IsClosed(geom), ST_IsSimple(geom)
FROM (SELECT 'LINESTRING(0 0, 0 1, 1 1, 1 0, 0 0)'::geometry AS geom) AS foo;
st_isring | st_isclosed | st_issimple
-----------+-------------+-------------
t | t | t
(1 row)
SELECT ST_IsRing(geom), ST_IsClosed(geom), ST_IsSimple(geom)
FROM (SELECT 'LINESTRING(0 0, 0 1, 1 0, 1 1, 0 0)'::geometry AS geom) AS foo;
st_isring | st_isclosed | st_issimple
-----------+-------------+-------------
f | t | f
(1 row)