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Enterprise Location Referencing System – Transportation (ELRS-T)
Narayanan Ramanathan
Project Manager
GIS &GPS CoE –HCL Technologies Ltd
narayananrn@hcl.in
Ravi B
Associate Software Engineer
HCL Technologies Ltd
ravibalakrishnan@hcl.in
Vadivelan P
Software Engineer – HCL Technologies Ltd
vadivelanp@hcl.in
Abstract
Transportation organisations have historically defined their asset locations based on the linear referencing methods like mile posts, reference markers e.t.c. The advent of GPS has revolutionized the process of data collection. This has led us to a precarious situation where there are inconsistencies in the actual location of the asset or incident on the road. In addition, there is no platform to correlate and analyse asset data of a road obtained from multiple methods. This paper attempts to design an Enterprise Location Referencing System for Transportation (ELRS-T) which contains multiple location reference methods, each referring assets and incidents within their reference framework. The architecture and the components of ELRS-T has been identified and summarized to address two key important requirements viz. transformation of the location of the asset or incident data among methods of ELRS-T and the persistence of the asset data on the road, subjected to temporal attenuations. The ELRS-T would serve as an ideal tool for the transportation managers to study transportation asset or incident parameters under a common framework and achieve data flow among systems.
1. Introduction
The road Infrastructure is a key accelerator for the growth of a nation. The transportation organizations rely on the discrete systems and applications to automate and facilitate operations associated with the roads. Majority of the road transportation systems are required to reference the asset or incident locations on the road. Traditionally, the road asset and the incident location are marked by linear reference methods like mile post, mileage, distance past reference markers and many others. GPS is the latest addition that has revolutionized the data collection process with its ease and accuracy. The location methods are independent and often do not give consistent view of the road network. Thus, it is hampers the swift flow of information from one system to another for combined analysis. The goal of the paper is to define an Enterprise Location Referencing System for Transportation (ELRS-T) which highlights the maintainability of the integrity of the asset or incident location when it is being transformed from one method to another. The paper also explains the persistence of the location component of the asset / incident data, adapting to the temporal changes of the road network.
2. GPS and Linear Referencing
The linear reference methods refer an asset with respect to a permanent feature and linear distance from it, measured usually using tedious distance measuring equipments. However, the advent of GPS technology has enabled the transportation managers to swiftly record the location of assets and incidents. Nevertheless, it is easy for the field inspectors who perform maintenance operations to identify the assets based on the linear distance from the milepost rather than GPS co-ordinates. For instance, describing the location of an accident as “1/2 km west of km-post 149 on National Highway-5,” is more easily understood by the rescue team driver than a set of coordinates. The situation can be addressed by the implementation of a system where asset and incident locations are available in linear methods (mile post, reference marker), Latitude and Longitude and Street Addresses.
3. Location Referencing System
According to NCHRP (1974), the Location Referencing Method (LRM) is a technique to identify a specific point or section of road either in the office or in the field. Location Referencing System (LRS) encompasses set of field and office procedures to retrieve records of specific point on a highway. In general, the available location reference methods can be classified as
- Geodetic Reference Method
In the Geodetic reference method, the asset and the event locations are marked based on the three dimensional orthogonal co-ordinate system with origin at the Earth’s center. GPS is a geodetic reference method and adopts WGS 84 datum.
- Linear Reference Method
Linear Reference Methods are one-dimensional methods as the road asset and the incident locations are indicated as the linear distance/offset from a known point. Linear Reference Methods were widely used by the transportation agencies before the advancement of GPS.
- Geometric Referencing Method
Alternatively referred as the co-ordinate reference method, this method would be used to display the road asset and event locations on a map. Besides viewing and editing asset locations on the road network, the method is imperative for the transformation of the location of the asset among the linear and the GPS method.
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