13.4.2 The OpenGIS Geometry Model

13.4.2.1 The Geometry Class Hierarchy

13.4.2.2 Geometry Class

13.4.2.3 Point Class

13.4.2.4 Curve Class

13.4.2.5 LineString Class

13.4.2.6 Surface Class

13.4.2.7 Polygon Class

13.4.2.8 GeometryCollection Class

13.4.2.9 MultiPoint Class

13.4.2.10 MultiCurve Class

13.4.2.11 MultiLineString Class

13.4.2.12 MultiSurface Class

13.4.2.13 MultiPolygon Class

The set of geometry types proposed by OGC's SQL with Geometry Types environment is based on the OpenGIS Geometry Model. In this model, each geometric object has the following general properties:

• It is associated with a spatial reference system, which describes the coordinate space in which the object is defined.

• It belongs to some geometry class.