GISs are closely related to several other types of information
systems, but it is the ability to manipulate and analyze geographic
data that sets GIS technology apart. Although there are no hard
and fast rules about how to classify information systems, the
following discussion should help differentiate GIS from desktop
mapping, computer-aided design (CAD), remote sensing, DBMS, and
global positioning systems (GPS) technologies.
A desktop mapping system uses the map metaphor to organize data
and user interaction. The focus of such systems is the creation
of maps: the map is the database. Most desktop mapping systems
have more limited data management, spatial analysis, and customization
capabilities. Desktop mapping systems operate on desktop computers
such as PCs, Macintoshes, and smaller UNIX workstations.
CAD systems evolved to create designs and plans of buildings and
infrastructure. This activity required that components of fixed
characteristics be assembled to create the whole structure. These
systems require few rules to specify how components can be assembled
and very limited analytical capabilities. CAD systems have been
extended to support maps but typically have limited utility for
managing and analyzing large geographic databases.
Remote Sensing and GPS
Remote sensing is the art and science of making measurements of
the earth using sensors such as cameras carried on airplanes,
GPS receivers, or other devices. These sensors collect data in
the form of images and provide specialized capabilities for manipulating,
analyzing, and visualizing those images. Lacking strong geographic
data management and analytical operations, they cannot be called
Database management systems specialize in the storage and management
of all types of data including geographic data. DBMSs are optimized
to store and retrieve data and many GISs rely on them for this
purpose. They do not have the analytic and visualization tools
common to GIS.