EnvelopeCenter (geography Data Type )

**APPLIES TO:** SQL Server (starting with 2008) Azure SQL Database Azure SQL Data Warehouse Parallel Data Warehouse

Returns a point that can be used as the center of a bounding circle for the geography instance.

To determine the bounding circle, each point in the instance is described as a vector from the center of the Earth to the point on the Earth’s surface. The center point of the bounding circle is calculated by averaging all of the vectors. For closed loops, either in a polygon instance or a linestring instance, the first and last point is used only once.

This geography data type method supports FullGlobe instances or spatial instances that are larger than a hemisphere.

Syntax

  
EnvelopeCenter( )  

Return Types

SQL Server return type: geography

CLR return type: SqlGeography

Remarks

This method returns a point. When used with EnvelopeAngle(), EnvelopeCenter() returns a bounding circle of a geography instance.

[!NOTE]
EnvelopeCenter() returns a bounding circle for a geography instance, but the results are not guaranteed to produce the minimal bounding circle. In contrast, the geometry data type method STEnvelope() is guaranteed to return the minimum bounding box when it is applied to a geometry instance.

In SQL Server 2012 (11.x) and higher, returns the center of the circle representing the envelope of this instance as a point. For all large objects as defined by EnvelopeAngle() = 180, EnvelopeCenter() will return (90,0).

This method is not precise.

Examples

DECLARE @g geography = 'LINESTRING(-120 45, -120 0, -90 0)';  
SELECT @g.EnvelopeCenter().ToString();  

See Also

Extended Methods on Geography Instances
EnvelopeAngle (geography Data Type)