ST_Dimension

Determine the dimension of a geometry, or the highest dimension of the contents of a geometry collection.

Note that the dimension of a geometry is not the same thing as the number of coordinate dimensions. For example, a point geometry that is defined with x and y coordinates has 2 coordinate dimensions but a geometry dimension of 0.

Syntax

ST_Dimension(geo);

geo: The input geometry.
Type: ST_GEOMETRY(ANY)

Returns

A value of type INT that indicates the dimension of a geometry or, for a geometry collection, the dimension of the object with the highest dimension:

0: The geometry is a point.
1: The geometry is a line.
2: The geometry is a polygon.
-1: The geometry collection is empty.

Examples

SELECT inza..ST_Dimension(inza..ST_WKTToSQL('POINT (0 0)'));

ST_DIMENSION
------------
0
(1 row)

SELECT inza..ST_Dimension(inza..ST_WKTToSQL('LINESTRING (0 0, 1 1)'));

ST_DIMENSION
------------
1
(1 row)

SELECT inza..ST_Dimension(inza..ST_WKTToSQL('POLYGON ((1 1, 1 2, 2 2, 2 1, 1 1))'));

ST_DIMENSION
------------
2
(1 row)