geometry Data Type Method Reference
Microsoft SQL Server 2008 supports a set of methods for the geometry spatial data type. These methods include methods on geometry that are defined by the Open Geospatial Consortium (OGC) standard and a set of Microsoft extensions to that standard.
The error tolerance for the geometry methods can be as large as 1.0e-7 * extents. The extents refer to the approximate maximal distance between points of the geometry object.