The geometry and geography data types support sixteen spatial data objects, or instance types. However, only eleven of these instance types are instantiable; you can create and work with these instances (or instantiate them) in a database. These instances derive certain properties from their parent data types that distinguish them as Points, LineStrings, CircularStrings, CompoundCurves, Polygons, CurvePolygons or as multiple geometry or geography instances in a GeometryCollection. Geography type has an additional instance type, FullGlobe.
The figure below depicts the geometry hierarchy upon which the geometry and geography data types are based. The instantiable types of geometry and geography are indicated in blue.