Designing and Implementing Spatial Storage (Database Engine)
Spatial data represents information about the physical location and shape of geometric objects. These objects can be point locations or more complex objects such as countries, roads, or lakes.
SQL Server supports two spatial data types: the geometry data type and the geography data type. Both data types are implemented as .NET common language runtime (CLR) data types in SQL Server.
The geometry data type (planar) supported by SQL Server conforms to the Open Geospatial Consortium (OGC) Simple Features for SQL Specification version 1.1.0.
For more information on OGC specifications, see the following:
SQL Server supports a subset of the existing GML 3.1 standard which is defined in the following schema: http://schemas.microsoft.com/sqlserver/profiles/gml/SpatialGML.xsd.