ABSTRACT
Before defining a geographic information system (GIS), a brief explanation of the ‘‘information systems’’ concept is helpful. Information systems not only retrieve data, but also combine data with services or actions that allow a user to see trends or patterns in the data. A GIS, therefore, should be an information system that, more than other types of information systems, manages geographically based data. Like earlier mapping systems, a GIS can draw maps either electronically or on paper. As an information system, a GIS can also derive new maps from maps already within it. The underlying definition for a GIS in this chapter is ‘‘a system of hardware and software
tation of geographic information.’’ This definition stresses that a GIS should provide tools for bringing in data, for managing that data, for analyzing the data, and for getting information out of it.
