STNumCurves (geography Data Type)

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

Returns the number of curves in a one-dimensional geography instance.




To view Transact-SQL syntax for SQL Server 2014 and earlier, see Previous versions documentation.

Return Types

SQL Server return type: geography

CLR return type: SqlGeography


One-dimensional spatial data types include LineString, CircularString, and CompoundCurve. An empty one-dimensional geography instance returns 0.

STNumCurves() works only on simple types; it does not work with geography collections like MultiLineString. NULL is returned when the geography instance is not a one-dimensional data type.

Null is returned for uninitialized geography instances.


A. Using STNumCurves() on a CircularString instance

The following example shows how to get the number of curves in a CircularString instance:

 DECLARE @g geography; 
 SET @g = geography::Parse('CIRCULARSTRING(-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653)');  
 SELECT @g.STNumCurves();

B. Using STNumCurves() on a CompoundCurve instance

The following example uses STNumCurves() to return the number of curves in a CompoundCurve instance.

 DECLARE @g geography;  
 SET @g = geography::Parse('COMPOUNDCURVE(CIRCULARSTRING(-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))');  
 SELECT @g.STNumCurves();

See Also

Spatial Data Types Overview
OGC Methods on Geography Instances