PostGIS

ST_Dimension

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7.4. Geometry Accessors

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Name

ST_Dimension — Returns the topological dimension of a geometry.

Synopsis

integer +`*`+ST_Dimension*(`geometry `g`)`;

Description

Return the topological dimension of this Geometry object, which must be less than or equal to the coordinate dimension. OGC SPEC s2.1.1.1 - returns 0 for POINT, 1 for LINESTRING, 2 for POLYGON, and the largest dimension of the components of a GEOMETRYCOLLECTION. If the dimension is unknown (e.g. for an empty GEOMETRYCOLLECTION) 0 is returned.

check This method implements the SQL/MM specification.

SQL-MM 3: 5.1.2

Enhanced: 2.0.0 support for Polyhedral surfaces and TINs was introduced. No longer throws an exception if given empty geometry.

Note

Prior to 2.0.0, this function throws an exception if used with empty geometry.

check This function supports Polyhedral surfaces.

check This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

SELECT ST_Dimension('GEOMETRYCOLLECTION(LINESTRING(1 1,0 0),POINT(0 0))');
ST_Dimension
-----------
1

See Also

ST_NDims

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ST_CoordDim

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