SQL Server supports several extensions to the static geography methods of the Open Geospatial Consortium (OGC).
For more information on OGC specifications, see the following resources:
OGC Specifications, Simple Feature Access Part 1 - Common Architecture
OGC Specifications, Simple Feature Access Part 2 – SQL Options
OGC Specifications, Geography Markup Language
Static Aggregate Geography Methods
OGC Methods on Geography Instances
Extended Methods on Geography Instances
OGC Static Geography Methods