GeometryCollection
Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance SQL analytics endpoint in Microsoft Fabric Warehouse in Microsoft Fabric SQL database in Microsoft Fabric
A GeometryCollection is a collection of zero or more geometry or geography instances. A GeometryCollection can be empty.
For a GeometryCollection instance to be accepted, it must either be an empty GeometryCollection instance or all the instances comprising the GeometryCollection instance must be accepted instances. The following example shows accepted instances.
DECLARE @g1 geometry = 'GEOMETRYCOLLECTION EMPTY';
DECLARE @g2 geometry = 'GEOMETRYCOLLECTION(LINESTRING EMPTY,POLYGON((-1 -1, -1 -5, -5 -5, -5 -1, -1 -1)))';
DECLARE @g3 geometry = 'GEOMETRYCOLLECTION(LINESTRING(1 1, 3 5),POLYGON((-1 -1, -1 -5, -5 -5, -5 -1, -1 -1)))';
The following example throws a System.FormatException
because the LinesString instance in the GeometryCollection instance is not accepted.
DECLARE @g geometry = 'GEOMETRYCOLLECTION(LINESTRING(1 1), POLYGON((-1 -1, -1 -5, -5 -5, -5 -1, -1 -1)))';
A GeometryCollection instance is valid when all instances that comprise the GeometryCollection instance are valid. The following shows three valid GeometryCollection instances and one instance that is not valid.
DECLARE @g1 geometry = 'GEOMETRYCOLLECTION EMPTY';
DECLARE @g2 geometry = 'GEOMETRYCOLLECTION(LINESTRING EMPTY,POLYGON((-1 -1, -1 -5, -5 -5, -5 -1, -1 -1)))';
DECLARE @g3 geometry = 'GEOMETRYCOLLECTION(LINESTRING(1 1, 3 5),POLYGON((-1 -1, -1 -5, -5 -5, -5 -1, -1 -1)))';
DECLARE @g4 geometry = 'GEOMETRYCOLLECTION(LINESTRING(1 1, 3 5),POLYGON((-1 -1, 1 -5, -5 5, -5 -1, -1 -1)))';
SELECT @g1.STIsValid(), @g2.STIsValid(), @g3.STIsValid(), @g4.STIsValid();
@g4
is not valid because the Polygon instance in the GeometryCollection instance is not valid.
For more information on accepted and valid instances, see Point, MultiPoint, LineString, MultiLineString, Polygon, and MultiPolygon.
The following example instantiates a geometry
GeometryCollection
with Z values in SRID 1 containing a Point
instance and a Polygon
instance.
DECLARE @g geometry;
SET @g = geometry::STGeomCollFromText('GEOMETRYCOLLECTION(POINT(3 3 1), POLYGON((0 0 2, 1 10 3, 1 0 4, 0 0 2)))', 1);