Overview
The geometry data type stores planar spatial data. SQL Server provides a rich set of methods for performing geometric calculations and analysis on geometry instances.
Geometric Functions
| Function | Description | Syntax |
|---|---|---|
STArea() |
Returns the area of the geometry instance. | geom.STArea() |
STLength() |
Returns the length of the geometry instance. | geom.STLength() |
STIsEmpty() |
Indicates whether the instance is empty. | geom.STIsEmpty() |
STIsClosed() |
Specifies if a LineString is closed. | geom.STIsClosed() |
STNumPoints() |
Returns the number of points in the instance. | geom.STNumPoints() |
STPointN(n) |
Returns the nth point of the instance. | geom.STPointN(n) |
STConvexHull() |
Returns the smallest convex geometry that encloses the instance. | geom.STConvexHull() |
STIntersection(geom2) |
Returns the geometric intersection of two instances. | geom1.STIntersection(geom2) |
STDifference(geom2) |
Returns the part of the first instance that does not intersect the second. | geom1.STDifference(geom2) |
STUnion(geom2) |
Returns a geometry that combines two instances. | geom1.STUnion(geom2) |
STBuffer(distance) |
Creates a buffer area around the geometry. | geom.STBuffer(distance) |
STEnvelope() |
Returns the rectangular envelope of the instance. | geom.STEnvelope() |
STAsText() |
Returns the Well-Known Text (WKT) representation. | geom.STAsText() |
STGeomFromText(wkt, SRID) |
Creates a geometry instance from WKT. | geometry::STGeomFromText(wkt, SRID) |
STPointFromText(wkt, SRID) |
Creates a point from WKT. | geometry::STPointFromText(wkt, SRID) |
Examples
DECLARE @g geometry = geometry::STGeomFromText('POLYGON((0 0,0 10,10 10,10 0,0 0))',0);
SELECT @g.STArea() AS Area,
@g.STLength() AS Perimeter,
@g.STEnvelope().STAsText() AS Envelope;