The Geospatial Revolution
by Silvio Manuel
This article serves to illustrate the explosion in Geographic Information Systems (GIS) that has paralleled the growth of the IT world in general.
It is a summary of:
- What a Geographic Information System is.
- The main software vendors involved in the GIS market.
- Why it is important to you.
This article is not a detailed explanation of GIS programming, nor does its scope encompass the intricate details of different GIS platforms. In short, this article's purpose is to provide the reader with a basic understanding of GIS without exploring the subject in intricate detail.
Geographic Information Systems finds its roots in two disciplines, Geography and Statistical Analyses.
The advent of computing, and more accurately, powerful microcomputing allowed the development of GIS systems. The core to any GIS is the ability to combine tabular data with an exact spatial location. A ready example can be found in census data, where enormous amounts of detailed information are located. By implementing this data into a GIS , he entire database can be queried, not only by database fields, but also by spatial requirements. This is equivalent to looking at a paper map of the United States which is filled with thumbtacks. Each thumbtack has a piece of paper attached, detailing the information about hat location. By using a GIS complex, analyses can be performed on a location.
The uses of a GIS are limited only by the ability of its owner and the data available. It has become popular in everything from city planning to ecological conservation. At the heart of he system lies a topological model to which he data is pinned. The data file, which is almost always vector-oriented (if it is not vector then some means must be available to emulate this), is populated with a database or me, records.
The spatial pieces of the data, which resemble its real world counterpart, are comprised of points, lines, and polygons. Since the file has topology, every line has a "right" and a "left," and every polygon has an "in" and an "out." This is how each database record is linked to its spatial coordinates. The most visible example of this is your local emergency 911 system.
Most E911 systems across the country are now based on a GIS. This is the reason all rural routes were given E911 addresses, so that they could be more easily located (and this also makes them more easily assimilated into the GIS database).
When you tell the E911 operator your address, (and I don't even think it's necessary to tell them anymore), it is fed through the GIS. The address is analyzed (it is either a left or a right address), then the appropriate record in the GIS is found using this code. Once the record is located, GIS utilities like ESRI's Network Analyst can determine the quickest route from several different locations, taking into consideration traffic flow, traffic congestion, and any other variables for which data is available.
This is a simple example, and I have seen much more complex uses. What makes this a viable system is its:
Several GIS packages are available commercially, but the most popular are MapInfo, MGE, ArcView, GeoMedia, and ArcInfo. MGE is based on the MicroStation CAD engine, developed by Bentley Systems and Intergraph. ArcView and ArcInfo are both distributed by Environmental Systems Research Institute, commonly called ESRI.
In the past Intergraph's packages dominated the GIS market but the last five years have seen ESRI rise to almost total dominance. This lead has been due to the company's devotion to distributing its software to educational institutions at large discounts, thus creating a trained workforce in college graduates, and to its scriptability.
ArcView has its own scripting language, Avenue, that is simple but useful. Thousands of programs for specific tasks are easy to find on the Internet or from ESRI themselves. If a program is not available then one can be produced at little or no cost. This means that anyone can purchase he basic ArcView package and then tailor it to their specific needs.
So, why is any of this important? And how does it affect you? Anyone with even a little imagination can see how a system that can integrate and analyze huge databases with spatial data to create targeted, specific results in he form of maps, graphics, projections, etc. can be misused. And it is.
Some companies deal in this information. The spatial data is cheap, well, it's actually free. An almost limitless amount of geographic data is available from the United States Geological Survey, TerraServer, and other such sites. This data is being collected by some companies, who then assimilate the spatial information with massive databases compiled from grocery stores, mailing lists, credit reports, census data, and public records.
This information is then sold to groups who use it in conjunction with a GIS to determine everything from lending qualifications to high crime areas. To 99.9 percent of the population, this goes on without their awareness or consent. If you apply for anything from health insurance to a loan, a company possessing such a database can reference your info and study where you live, what you eat, what you buy, and with a little guesswork, why you buy it. To many readers of 2600 this isn't a new idea, and to others it may seem a "conspiracy theory" or paranoid sci-fi delusion. Yet it is an absolute reality.
For a detailed description of such practices, check out:
Protecting Personal Privacy in Using Geographic Information Systems, Photogrammetric Engineering and Remote Sensing, Vol. 60, No. 9, September 1994 pp. 1083-1095
We Know Who You Are and We Know Where You Live: The Instrumental Rationality of Geodemographic Systems, Jon Goss, Dept. of Geography, Univ. of Hawaii.
The bottom line is that very soon in the future these systems will be an everyday part of our lives, with the possibility existing for them to be used or abused. Thus, it is necessary to have at least a basic understanding of them, how they are used, and how they affect you.
This article has skimmed over a great deal, but hopefully will provide answers to the above questions. So keep an eye out, because someone really is watching you, and it ain't that guardian angel you keep talking about!