InstanceOf (geography Data Type)
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Tests if the geography instance is the same as the specified type.
Syntax
.InstanceOf ( 'geography_type')
Arguments
geography_type
The nvarchar(4000) string specifying one of 16 types exposed in the geography type hierarchy.
Return Types
SQL Server return type: bit
CLR return type: SqlBoolean
Remarks
Returns 1 if the type of a geography instance is the same as the specified type, or if the specified type is an ancestor of the instance type; otherwise, returns 0.
This geography data type method supports FullGlobe instances or spatial instances that are larger than a hemisphere.
The input for the method must be one of these types: Geometry, Point, Curve, LineString, CircularString, Surface, Polygon, CurvePolygon, GeometryCollection, MultiSurface, MultiPolygon, MultiCurve, MultiLineString, MultiPoint, or FullGlobe.
This method throws an ArgumentException if you use any other strings for the input.
This method isn't precise.
Examples
The following example creates a MultiPoint instance and uses InstanceOf() to see whether the instance is a GeometryCollection.
DECLARE @g geography;
SET @g = geography::STGeomFromText('MULTIPOINT(-122.360 47.656, -122.343 47.656)', 4326);
SELECT @g.InstanceOf('GEOMETRYCOLLECTION');