What is a Geographic Information System(GIS)?

Geographic information systems (GISs) and some of their major features are defined, the present status of some of the major technical elements of these systems are described, and some aspects of the standards appropriate to their technology are discussed. The history of GIS development is summarized and their present technological success is sketched. The present situation of each of their three major elements, computer hardware, computer software, and geographic data, is described. The major GIS hardware platforms (mainframes, minicomputers, workstations, microcomputers, and networked hardware), and their special peripheral devices (digitizers, plotters, scanners, etc.) are mentioned. GIS software is described, including its organization, major functions, and use in modeling and analysis in various applications. Their data and databases are described. Present major technological applications are listed and standards are discussed. The notion of GISs as “data integration machines” is introduced and implications are indicated.