Geographic Information System (GIS) has been defined in various ways by different authorities. A typical GIS can be understood by looking at its various definitions. In this section, we present different definitions (or descriptions) of GIS that have been offered by people.
Burrough (1986) defines GIS as a "set of tools for collecting, storing, retrieving at will, transforming and displaying spatial data from the real world for a particular set of purposes".
In his own definition, Arnoff (1989) defines GIS as "a computer based system that provides four sets of capabilities to handle geo-referenced data: data input, data management (data storage and retrieval), manipulation and analysis, and data output."
“A geographic information system (GIS) is a computer-based tool for mapping and analysing things that exist and events that happen on earth. GIS technology integrates common database operations such as query and statistical analysis with the unique visualisation and geographic analysis benefits offered by maps” (ESRI, 1990).
". . . The purpose of a traditional GIS is first and foremost spatial analysis. Therefore, capabilities may have limited data capture and cartographic output. Capabilities of analyses typically support decision making for specific projects and/or limited geographic areas. The map data-base characteristics (accuracy, continuity, completeness, etc.) are typically appropriate for small-scale map output. Vector and raster data interfaces may be available. However, topology is usually the sole underlying data structure for spatial analyses" (Huxhold, 1991 p.27).
"A geographic information system is a facility for preparing, presenting, and interpreting facts that pertain to the surface of the earth. This is a broad definition . . . a considerably narrower definition, however, is more often employed. In common parlance, a geographic information system or GIS is a configuration of computer hardware and software specifically designed for the acquisition, maintenance, and use of cartographic data" (Tomlin, 1990 p xi).
"A geographic information system (GIS) is an information system that is designed to work with data referenced by spatial or geographic coordinates. In other words, a GIS is both a database system with specific capabilities for spatially-reference data, as well as a set of operations for working with data . . . In a sense, a GIS may be thought of as a higher-order map" (Star and Estes, 1990, pp. 2-3).
A GIS is "an organised collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyse, and display all forms of geographically referenced information" (ESRI, 1990, pp. 1-2).
“A Geographic Information System (GIS) is a collection of computer hardware, software and geographic data used to analyse and display geographically referenced information” (URL1).
“A GIS is a computer system capable of capturing, storing, analysing, and displaying geographically referenced information; that is, data identified according to location. (Some GIS) practitioners also define a GIS as including the procedures, operating personnel, and spatial data that go into the system” (URL2).
“In the strictest sense, a GIS is a computer system capable of assembling, storing, manipulating, and displaying geographically referenced information, i.e. data identified according to their locations. GIS practitioners also regard the total GIS as including operating personnel and the data that go into the system” (URL2).
“GIS is an integrated system of computer hardware, software, and trained personnel linking topographic, demographic, utility, facility, image and other resource data that is geographically referenced” (URL3).
A list of additional definitions of GIS can be found in Longley et al (2001). By way of summary, GIS can be considered to be a computer-based system comprising hardware, software, geographically-referenced data, personnel and procedures put together for the input, storage, retrieval, analysis, manipulation, query, update and output of geographical data.
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