GEOG 482
The Nature of Geographic Information

1. Overview


When I started writing this text in 1997, my office was across the street (and, fortunately, upwind) from Penn State's power plant. The energy used to heat and cool my office is still produced there by burning natural gas extracted from wells in nearby counties. Combustion transforms the potential energy stored in the gas into electricity, which solves the problem of an office that would otherwise be too cold or too warm. Unfortunately, the solution itself causes another problem, namely emissions of carbon dioxide and other more noxious substances into the atmosphere. Cleaner means of generating electricity exist, of course, but they, too, involve transforming energy from one form to another. And cleaner methods cost more than most of us are willing or able to pay.

It seems to me that a coal-fired power plant is a pretty good analogy for a geographic information system. For that matter, GIS is comparable to any factory or machine that transforms a raw material into something more valuable. Data is grist for the GIS mill. GIS is like the machinery that transforms the data into the commodity--information--that is needed to solve problems or create opportunities. And the problems that the manufacturing process itself creates include uncertainties resulting from imperfections in the data, intentional or unintentional misuse of the machinery, and ethical issues related to what the information is used for, and who has access to it.

This text explores the nature of geographic information. To study the nature of something is to investigate its essential characteristics and qualities. To understand the nature of the energy produced in a coal-fired power plant, one should study the properties, morphology, and geographic distribution of coal. By the same reasoning, I believe that a good approach to understanding the information produced by GIS is to investigate the properties of geographic data and the technologies and institutions that produce it.


The goal of Chapter 1 is to situate GIS in a larger enterprise known as Geographic Information Science and Technology (GIS&T), and in what the U.S. Department of Labor calls the "geospatial industry." In particular, students who successfully complete Chapter 1 should be able to:

  1. define a geographic information system;
  2. recognize and name basic database operations from verbal descriptions;
  3. recognize and name basic approaches to geographic representation from verbal descriptions;
  4. identify and explain at least three distinguishing properties of geographic data; and
  5. outline the kinds of questions that GIS can help answer.

Comments and Questions

Registered students are welcome to post comments, questions, and replies to questions about the text. Particularly welcome are anecdotes that relate the chapter text to your personal or professional experience. There are discussion forums available in the Canvas course management system for comments and questions.

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Students who register for this Penn State course gain access to assignments and instructor feedback, and earn academic credit. Information about Penn State's Online Geospatial Education programs is available at the Geospatial Education Program Office.