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Transportation modeling and GIS
Bharat Salhotra
This paper highlights the use of Geographical Information
System for Investment Planning in the Rail transportation sector.
Indian
Railways is one of the largest transport systems in the world with a total of
over 60,000 track kilometers spanning the length and breadth of India. About 14
million passengers - about the population of Australia- and over one million
tons of freight traffic move over this network every day with a fleet of 6100
locomotives and half a million fleet cars. Indian Railways, is truly the
lifeline of India and contributes over 1% of the national GDP, with its annual
revenues aggregating to nearly 10 billion dollars.
One of the
peculiarities of basic infrastructure - transport, power transmission and
telecommunications, - is that it forms and operates as a part of a
geographically spread out network industry. As a result, a change in
infrastructure / operating practices in one part of the network has a
significant impact over other parts of the network. This "ripple effect"
translates into complexities for investment planning wherein benefits visualized
through additional investment often do not result in achieving the desired
objectives. In the absence of a strategic model that 'sees' the network as a
whole, infrastructure-related investments tend to result in optimizing
sub-systems and simultaneously rendering the entire network system sub-optimal.
A realization of this 'ripple effect' and problems of subsystem optimization has
lead to the application of operation research based transportation
models.
Growth of transport infrastructure involves a lifecycle of
planning, design, construction followed by operation and maintenance (see Adams
et al 1992) and spatial data is central to each of these phases. An overwhelming
amount of transportation data is location based and geographically referenced
and in the light of this, GIS has emerged as the optimal technology to manage
this data. There is also a growing realization among transportation experts that
design and development of an integrated transport information system requires
Geographical Information System.
Research worldwide has attempted to
enhance the power of GIS by adding /attaching 'TM' i.e. transportation modeling
to the GIS so as to develop an integrated Geographical Information System for
transportation. However, looking at the complexities in network modeling in
general and peculiarities in transportation modeling in particular, it is not
feasible to develop a universal GIS-T for meeting the requirements of all the
users. Dedicated GIS-T software for meeting specific user requirements is
however, a strong possibility. One such successful case study is the Indian
Railways Long-Range Decision Support System (LRDSS)
The long-range
Decision Support System (LRDSS) project was started in 1994 as a joint effort
between World Bank and a team of Indian Railway Officers. The objective of the
LRDSS was the development of a scientific and data based system for drawing up
investment plans for track, rolling stock, and locomotives for the Indian
Railways network.
The LRDSS has been developed as a decision support
tool for facilitating pre-feasibility level analysis of investment alternatives
and for prioritization of projects based on their financial viability. In its
present form, LRDSS is being used as a strategic planning tool for drawing up
long term investment plans for Indian Railways. It provides an objective,
information based, interdisciplinary platform for evaluating different
investment alternatives aimed at improving the network wide capability of Indian
Railways.
A unique feature of the LRDSS is the Avenue based User
Interface, which insulates the planner from complex transportation models and
gigabytes of network data as well as transport forecasts, and at the same time,
provides him with a very powerful tool for long term planning. The GIS
capability at the front end provides top-level decision-makers with a usable
state of the art investment analysis tool. The GIS front end facilitates quick
evaluation of specific technology, policy, and market related initiatives on a
system-wide basis. In addition, the GIS is used for doing some preliminary
infrastructure related analysis.
LRDSS consists of six modules and each
of these modules is envisaged to work in a stand-alone mode as well as an
integrated whole. All the six modules reside at the back end while the front end
and the user interface uses ArcView. A brief description of each module is given
below:
Traffic Forecasting Module (TFM): This module is used to obtain the total
transport demand between pairs of points for different commodities and for
different key years. The inputs used by this module include production and
consumption forecasts for ten major commodities for the entire country and for
the next fifteen years. The data is based on extensive studies done by the
Planning Commission and relevant ministries from time to time. In addition, and
as a part of the data collection effort, Rail India Technical and Economic
Service (RITES) were retained for conducting road survey to assess the road
traffic levels that can be attracted to Rail.
The TFM uses Linear
Programming and "Furness" and factoring techniques for different commodities and
generates a commodity wise Origin Destination (O-D) traffic forecast
matrix.
The module as well as databases reside at the back end of the
User Interface and the front end Arc View is used to generate and view useful
maps that bring out the pattern of traffic - both by Rail and Road- between
pairs of points. These maps can be generated for different commodities,
different pairs of points and different key years. The user interface also
enables the user to generate "Origin Analysis" maps and "Destination Analysis"
maps for different commodities/years. The sample map below brings out the
outflow of traffic from Satna Area in Madhya Pradesh. While this sample map has
been drawn for all the commodities, the user interface allows the user to select
a specific commodity, a specific key year and a specific originating
area.
Maps of the type shown above help the decision-maker to better
appreciate the traffic movement potential as well as traffic leads for specific
commodities. These outputs help to initiate corrective action and optimally
deploy resources - wagons, locomotives so as to improve the market share. The
quantum of traffic is gauged by the thickness of the red lines as shown
above.
In addition to its presentation power, the User Interface can be
used for altering the assumptions used during traffic forecasting and for
running complex LP based models at the back end for generation of the O-D
traffic forecast by commodity.