ST_Dimension method

geometry-expression.ST_Dimension()

SMALLINT Returns the dimension of the geometry-expression as a SMALLINT between -1 and 2.

The ST_Dimension method returns the spatial dimension occupied by a geometry. The following values may be returned:

-1 The geometry corresponds to the empty set.
0 The geometry consists only of individual points (for example, an ST_Point or ST_MultiPoint).
1 The geometry contains at least one curve and no surfaces (for example, an ST_LineString or ST_MultiCurve).
2 The geometry consists of at least one surface (for example, an ST_Polygon or ST_MultiPolygon).

When computing the dimension of a collection, the largest dimension of any element is returned. For example, if a geometry collection contains a curve and a point, ST_Dimension returns 1 for the collection.

See How spatial dimensions work.

Note

By default, ST_Dimension uses the original format for a geometry, if it is available. Otherwise, the internal format is used. For more information about internal and original formats, see STORAGE FORMAT clause, CREATE SPATIAL REFERENCE SYSTEM statement.

SQL/MM (ISO/IEC 13249-3: 2006) 5.1.2

The following example returns the result 0.

SELECT NEW ST_Point(1.0,1.0).ST_Dimension()

The following example returns the result 1.

SELECT NEW ST_LineString('LineString( 0 0, 1 1)' ).ST_Dimension()

ST_Dimension method

Syntax

Returns

Remarks

Note

See also

Standards and compatibility

Example