Tricks of the Trade
Requirements to GIS applications
The effective use of Operations Research techniques in a GIS environment raises a number of
issues. In fact it imposes requirements on the GIS environment, the O.R. software, the network
data model, the spatial model for the geographic data used as well as on data quality.
To allow the integration of O.R. software in a GIS environment, both software components have
to be open. It should be possible to build integrated solutions using standard interfaces.
Furthermore the O.R. software should allow human intervention as a good design is usually
generated by cooperation between man and machine. From the point of view of the utility
company it is desirable that the GIS software and the design software are independent software
components. Only then the choice of the GIS software does not influence the choice of the O.R.
software and a component can be replaced when required.
Network design requires an adequate network data model in the GIS system. Part of the design
process is network calculation. Network calculation requires integrated data about the location,
the components, and the characteristics of the components and the connectivity of the network.
Obviously scanned raster images will not do. The data structure of standard drafting software
generally does not handle location and technical characteristics of components in an integrated
way. Also, the most advanced GIS software is not always used to its full capacity since the
requirements for network design were not considered at the time of data model design or
regarded as too costly during data conversion.
The network design uses a range of “background” geographic information and consequently
makes demands on these data. If you want to generate a network parallel to the street edges,
the base map should contain all relevant street edges and these should be gee-coded as such.
Also, the street edges should be modeled adequately as “polylines” (strings of lines and arcs).
Short polylines (in particular if they consist of one line or arc) will have a dramatic effect on
computer processing time. Also, the endpoints of these polylines should coincide exactly. In
summary: The ideal base map for network design has a topological structure. Where land use
data or road surface data is used, again this surface related data has to have a topological
structure in order to calculate the length of network in a particular area.
Even an excellent GIS system does not guarantee the implementation of a good data model
and even an excellent data model does not guarantee good quality data. Visual inspection of
data on the screen or on a plotted map does not tell everything about data quality. The more
advanced analysis and design applications are the real test for your GIS data. Network
connectivity and topological structure can only be controlled by automated procedures. This
must be available when the data is converted and when the data is updated. If these quality
control procedures are not in place data quality will deteriorate in the long run. On the other
hand ruthless data quality control is the key to improved company performance and customer
satisfaction.
Conclusion
The use of Operations Research techniques in combination with GIS is still in its
infancy. This paper has focussed on the integration of O.R. techniques with network design. An
equally important area in the competitive utility world is the planning and routing of service and
repair engineers. Clearly, customer satisfaction is directly affected by efficient correction of
failures and outages. In addition to the requirements that have been discussed in the previous
chapter, excellent means of communication between a planner and the field workers are a
necessity. Now these are coming available, tools to assist field operations that integrate GIS,
ERP-systems and O.R. techniques will emerge. In fact, integration of information systems will
be the trend for the next decades as it will be the way to improve the competitiveness through
cost savings. In the unfortunate case that current GIS systems do not meet the requirements for
operations as discussed here, additional work will have to be done and additional costs will
have to be made. But the way to recover the costs of GIS systems is not in doing the old
manual process of record keeping the digital way. The only justification of these systems lies in
their full exploitation in the daily operations of the utility industry, even though that may require
business process re-engeneering.
The 20th century gave rise to an enormous leap in technology. In the utility
industry, it is just the beginning.
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