Z (geometry Data Type)
The Z (elevation) value of the instance. The semantics of the elevation value are user-defined.
Syntax
.Z
Return Types
SQL Server type: float
CLR type: SqlDouble
Remarks
The value of this property will be null if the geometry instance is not a point, as well as for any Point instance for which it is not set.
This property is read-only.
Z-coordinates are not used in any calculations made by the library and is not carried through any library calculations.
Examples
The following example creates a Point instance with Z (elevation) and M (measure) values and uses Z to fetch the Z value of the instance.
DECLARE @g geometry;
SET @g = geometry::STGeomFromText('POINT(1 2 3 4)', 0);
SELECT @g.Z;