Pitney Bowes MapXtreme - Manual (Page 382)

Chapter 21: Linear Referencing
What is Linear Referencing
MapXtreme v7.1 389 Developer Guide
What is Linear Referencing
Linear referencing is an alternative reference system to the traditional coordinate reference systems
that tie locations of linear features to points on the earth. Linear referencing is used in many fields,
including water resource management, transportation, and oil and gas exploration. Any physical
asset that you can map as part of a linear network can hold data that describes the asset or a
condition or event related to that asset. The data is stored as an M, or measure value, on the
MultiCurve object along with the X and Y coordinates for the location. The M values can then be
further mapped and analyzed for better resource management.
M values are the cornerstone of linear referencing. M values hold the measure, whatever it may be.
Points along a linear feature are referenced from an established known point that is relative to
something else. A classic example is the mile marker post along a highway. The ID of the mile
marker is some M value that refers to some distance from a known location, typically a highway
intersection or county boundary.
M values are commonly used by infrastructure and transportation data managers to better visualize,
query, monitor and analyze assets, conditions and events that exist along a line. For example, an
emergency call center operator can determine the location of a stranded motorist from the mile
marker the motorist provides to the operator. The mile marker location is already known to the call
center. With this information in hand, the call center can dispatch the appropriate personnel to the
proper location.
For an overview of the Geometry model that supports MultiCurves and M values, see Chapter 16:
Spatial Objects and Coordinate Systems .
Using M values for Linear Referencing
MapXtreme offers a number of operations that use the measure (M) value for MultiCurve geometries
to provide linear referencing and dynamic segmentation capabilities. The methods are defined as
part of an instantiable MapInfo.Geometry.LinearReferencingOperations class, which provides
flexibility for adding properties or extending behaviors as needed.
These operations allow you to show simultaneous multiple attributes of your linear network, known
as dynamic segmentation, without requiring the storage of multiple copies of the same geometry. For
example, a highway can be represented by separate linear features that represent pavement
condition, lane type, and pavement material. They are all representing the same real-world
geometry, but this gives you an easier view of multiple types of information.