What Is a Geographic Information System?
In 1988 the Federal Interagency Coordinating Committee defined the term
Geographic Information System in the following manner: "a system of
computer hardware, software, and procedures designed to support the capture,
management, manipulation, analysis, and display of spatially referenced data for
solving complex planning and management problems." In essence, such a
system is an electronic spreadsheet coupled with powerful graphic-manipulation
and display capabilities.
The three most important elements of a typical Geographic Information System
can be summarized as follows:
1. Cartographic capability
2. Data management capability
3. Analytical capability
The cartographic capabilities built into a Geographic Information System
permit the computer - amply aided by skilled human operators - to produce
accurate maps and engineering drawings in a convenient pictorial format. Once
the digital maps have been constructed and annotated, the computer is used to
manipulate the finished product in various specific ways to produce layered maps
bristling with colorful attribute symbols.
The data management capabilities enable the GIS operators to store and
manipulate map-related information in convenient graphic and non-graphic
formats. The storage and manipulation of the non-graphic information is often
called "attribute processing". Operators who are trained to handle the attribute
processing can select the desired map data to produce colorful reports laced with
a rich mixture of graphics, tabular information, and pictorial attributes.
The analytical capabilities associated with today's GIS software permit the
trained operators to process and interpret spatial, tabular, and graphical data in a
variety of useful ways. They can, for instance, measured the distance between
two points or determine the areas of the various shapes pictured on the screen.
The analytical capabilities also help the operators plan, design, and manage
such important resources as roads, buildings, bridges, and waterways with
maximum practical efficiency.
Reaping The Practical Benefits of GIS Technology
All around the world, government professionals, utility engineers, and efficiencyminded
entrepreneurs have been quietly investing tens of millions of dollars in
attempting to perfect a wide variety of Geographic Information Systems. The GIS
routines they have been financing are capable of storing, manipulating, and
analyzing complicated electronic maps to increase the efficiency of various largescale
operations including city planning, resource management, emergency
vehicle dispatch, and water distribution.
FIGURE 1. Even the simplest Geographic Information Systems contain a rich
mixture of graphical and alphanumeric information stored in a database that can
be manipulated electronically by trained human operators. The information
contained in the various layers can be combined, modified, analyzed, and
displayed in limitless combinations. The spatial information, its associated
attributes, and any necessary alphanumeric labels and notations are imaged and
printed using full-color computer-driven printers and video displays.
Regional and state governments, for example, use GIS to develop country maps,
devise the most efficient deployments for public buses, repair roads, collect
taxes, chart the spread of contagious diseases, and nail down new election
GIS technology is also being used in some of the most economically
underdeveloped countries in the world. As you will learn at a later blog,
technicians in Gambia, a tiny country on the West Coast of Africa, have been
using GIS processing techniques coupled with inexpensive Navstar GPS
receivers to monitor illegal fishing activities in their country's territorial waters.
Jack Dangermond, President of Environmental Systems Research; is convinced
that Geographic Information Systems will rapidly spread to other Third-World
countries whose citizens will experience immediate benefits. "GIS technology,
because of its low-cost, high reliability, user-friendliness and wide usefulness, will
be adopted by many users outside the highly developed technological societies,"
he asserts. "This offers tremendous promise for improving the future for billions
of people on planet Earth."
Of course, Geographic Information Systems will be broadly adopted by users
around the world only if sponsors can foresee measurable economic benefits.
Fortunately, for several decades, such benefits have been reported in industry
literature and by many users. In 1968, for instance, the Texas Electronic Service
Company introduced a grid-based load-management system for its massive
electrical transformers. Using rather primitive GIS techniques, company
technicians easily found and documented $1 billion in savings over a four-year
Similarly, when the Denver Water Department implemented a GIS-based system
for its engineering and planning functions, professional technicians on their staff
pinpointed immediate savings in time, energy, and labor. Before automation,
drafters typically spent two months turning out drawings for each set of 100
cross-sectional maps. After automation, those same products were typically
completed in less than two days