Edit

Share via

EnvelopeCenter (geography Data Type)

  • Article

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance

Returns a point that you can use as the bounding circle's center for the geography instance.

Each point in the instance is described as a vector. To figure out the bounding circle, the vector extends from the Earth's center to the point on the Earth's surface. The bounding circle's center point 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 isn't 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)