ST_ISCLOSED()

All functions > GEOSPATIAL > ST_ISCLOSED()

Returns TRUE if a geometry is closed (start point equals end point for lines; always TRUE for polygons and points).

Signatures

Is closed

Returns: TRUE if closed

ST_ISCLOSED(geo: T) → BOOLEAN

With:

• T : Custom types: GEOM_POINT | GEOM_LINESTRING | GEOM_POLYGON | GEOM_MULTIPOINT | GEOM_MULTILINESTRING | GEOM_MULTIPOLYGON | GEOM_MULTIANY

Signature notes:

• LineString: TRUE if the first and last vertices are equal
• MultiLineString: TRUE if all component lines are closed
• Point and Polygon: always TRUE
• GEOMETRY only; not supported on BigQuery
• Returns NULL if the input is NULL

Examples

SELECT
    f1 := ST_ISCLOSED(ST_GEOMFROMTEXT('LINESTRING (0 0, 1 1, 0 0)')), -- Closed line (start equals end)
    f2 := ST_ISCLOSED(ST_GEOMFROMTEXT('LINESTRING (0 0, 1 1, 2 0)')) -- Open line
;