STNumCurves (geography Data Type)

Article
11/19/2024

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance SQL database in Microsoft Fabric

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

Syntax

  
.STNumCurves()

Return Types

SQL Server return type: geography

CLR return type: SqlGeography

Remarks

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.

Examples

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();

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