Linear ReferencingLinear ReferencingLinear referencing enables you to locate points and spans along linear assets. You use linear referencing, for example, to locate point assets, features, attributes, and assigned work.
Linear referencing in the IBM Maximo Linear Asset Manager uses distance measures from known points along X, Y, and Z axes.
X axis. A distance along the length of the linear asset. This distance, the measure, is the distance from the beginning of the linear asset. You can also use an X offset to reference a known point along the linear asset, such as the distance from an intersection or a mile post.
Y axis. A distance to the right or left side of the linear asset. This distance is the Y offset. You measure it from reference values you define, such as centerline or right pavement edge.
Z axis. A distance above or below the linear asset. This distance is the Z offset. You measure it from reference values you define, such as road surface.
To work with your linear assets, you define one or more linear reference methods (LRMs, also call Location Reference Methods) that fit your business practices. To define an LRM, you specify units of measure and reference points for each of the axes. For example, you might define an LRM that uses miles for the measure (X axis) and feet for all the offset measurements.
The following examples illustrate how different enterprises use different LRMs. The examples provide a general description, not specific units of measure for all axes.
Kilometerpoint. Measures are in kilometers from the start of the linear asset, This method is also known as Distance Measuring Instrument (DMI), absolute LRM, or Document-oriented method.
Milepoint. Measures are in miles from the start of the linear asset. This method is also known as Distance Measuring Instrument (DMI), absolute LRM, or Document-oriented method.
Milepost. Measures are from previously defined mile posts. This method is also known as a relative LRM or sign-oriented method. Some roadways that do not have mile posts use roadside landmarks.
Station-Offset. An engineering method that establishes stations every 100 (or 200) feet and adds an offset to identify the exact location.
Milepost. Measures are from previously defined mile posts. Railway mileposts, unlike road mileposts, rarely exist at the labeled mileage. Mile Post 2 might be 5420 feet beyond Mile Post 1, and so on.
Chain Marker. A chain unit, used in land measurement prior to 1960, still exists as a means to identify linear locations. Originally 66 feet, it is also used today to identify a distance of 100 feet.
Stationing. An engineering method (also known as Station/Offset) that establishes stations every 100 (or 200) feet and adds an offset to identify the exact location.
Absolute Stationing. Station and offset values are converted to absolute measures. This method is also known as Calculated Measure. For example, if a pipeline segment starts at 10 + 100 (station 10 with an offset of 100), the calculated measure (with stations every 100 feet) is 1100.
Add/Modify Linear Referencing Methods