M (geometry Data Type)
The M (measure) value of the geometry instance. The semantics of the measure value are user-defined.
SQL Server type: float
CLR type: SqlDouble
The value of this property is 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.
M values are not used in any calculations made by the library and will not be carried through any library calculations.
The following example creates a Point instance with Z (elevation) and M (measure) values and uses M to fetch the M value of the instance.
DECLARE @g geometry; SET @g = geometry::STGeomFromText('POINT(1 2 3 4)', 0); SELECT @g.M;