M (geography Data Type)
The M (measure) value of the geography instance. The semantics of the measure value are user-defined but generally describe the distance along a linestring. For example, the measure value could be used to keep track of mileposts along a road.
Syntax
.M
Return Types
SQL Server type: float
CLR type: SqlDouble
Remarks
The value of this property is null if the geography 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.
Examples
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 geography;
SET @g = geography::STGeomFromText('POINT(-122.34900 47.65100 10.3 12)', 4326);
SELECT @g.M;