- 11.5.2.1 The Geometry Class Hierarchy
- 11.5.2.2 Geometry Class
- 11.5.2.3 Point Class
- 11.5.2.4 Curve Class
- 11.5.2.5 LineString Class
- 11.5.2.6 Surface Class
- 11.5.2.7 Polygon Class
- 11.5.2.8 GeometryCollection Class
- 11.5.2.9 MultiPoint Class
- 11.5.2.10 MultiCurve Class
- 11.5.2.11 MultiLineString Class
- 11.5.2.12 MultiSurface Class
- 11.5.2.13 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.