MsSqlSpatial is a Spatial Extensions for SQL Server 2005.
This project conforms to OGC Simple Features Specification for SQL Revision 1.1 and provides many useful features to power your GIS application.
* OGC Simple Features Specification for SQL Revision 1.1 conformant (non official but verifiable).
* 2D Geometries supported: Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, GeometryCollection.
* Predicate functions: Equals, Disjoint, Intersects, Touches, Crosses, Within, Contains, Overlaps, Covers, CoveredBy, Relate, IsWithinDistance.
* Spatial analysis functions: ConvexHull, Intersection, Union, Difference, SymDifference.
* Linear referencing functions: LineInterpolatePoint, LineLocatePoint, LineSubstring.
* Spatial relationship and processing functions: Distance, Length, Area, Buffer, Centroid, PointOnSurface, Simplify, Polygonize, LineMerge and many more.
* Coordinate systems aware: SRID, SetSRID, Transform.
* Spatial indexing: Simple but effective implementation using table-valued functions (FilterQuery, JoinFilterQuery, IsWithinDistanceQuery, RelateQuery)
* Aggregate functions that overcome the 8000 bytes limitation of normal user-defined aggregate functions: UnionAggregate, EnvelopeAggregate, IntersectionAggregate.
* GML support: AsGML function.
* Import from shapefiles and PostGIS tables.