What is a Linear Referencing System?A linear referencing system (LRS) is a set of methods for specifying a location as a distance, or offset, along a linear feature (e.g. centerline) from a site with a known location. This ability is made possible through the use of route features that have unique identifiers and a measure system (e.g. distance, time, etc.). The concept is similar to a ruler, in which each tick mark represents a distance from another tick mark for a given unit of measurement.
Maryland State Highway LRS ImplementationThe Maryland State Highway Administration’s (SHA) LRS is based on county, route and milepoint and uses a distance-based measure system. Distances are measured in 1/1000ths of a mile along a route, beginning and ending at jurisdictional boundaries. For a more accurate measurement, SHA uses driven mileage to calculate the distance of a route.
How Does MD SHA Use Linear Referencing?SHA uses linear referencing to manage highway-related assets and roadway characteristics that do not have explicit x,y coordinates. Recording asset location in terms of relative distance along a line allows for multiple sets of overlapping attributes to be assigned roadway measurements without also requiring the roadway feature be segmented where an attribute value changes.
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