What is GIS?

Many definitions of GIS have been put forward. Here are some:

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-referenced data, as well as a set of operations for working [analysis] with the data (Star and Estes, 1990).

A system for capturing, storing, checking, integrating, manipulating, analyzing and displaying data which are spatially referenced to the Earth (Chorley, 1987).

Automated systems for the capture, storage, retrieval, analysis, and display of spatial data (Clarke, 1990).

A system of hardware, software, and procedures designed to support the capture, management, manipulation, analysis, modeling and display of spatially-referenced data for solving complex planning and management problems (NCGIA lecture by David Cowen, 1989).

An integrated package for the input, storage, analysis, and output of spatial information... analysis being the most significant (Gaile and Willmott, 1989).

GIS are simultaneously the telescope, the microscope, the computer, and the xerox machine of regional analysis and synthesis of spatial data (Abler, 1988).