Dimension(g)

Returns the inherent dimension of the geometry value g. The result can
be -1, 0, 1, or 2. The meaning of these values is given in
http://dev.mysql.com/doc/refman/5.6/en/gis-class-geometry.html.

URL: http://dev.mysql.com/doc/refman/5.6/en/gis-general-property-functions.html

