Geographic information systems (GIS) are automated systems used to capture, edit, store, manipulate, analyze and display an infinite variety of spatial data. A GIS has three major components: a data base, a spatial analysis and modeling capability, and a means for graphic display. Cartography serves GIS technology in several ways. Data inputs to geographical information systems are commonly retrieved from existing maps through digitizing or scanning procedures. Converting cartographic information into geographical databases represents a major portion of GIS development. Data may be geographically referenced as it is collected through the use of Global Positioning System satellites (a network of satellites that send positioning data anywhere on earth) or through the use of automated procedures that assign geographic coordinates to street addresses. The link between maps and geographic information systems occurs in the graphical communication of the output of the GIS models.
Today cartography is closely associated with the broader field of scientific visualization. This technique takes the map reader beyond the printed page and shows them terrain as if they were flying in a helicopter, displays the predicted dispersion of oil days or months after a spill, or models the future growth of an urban area. Since the limitations of a paper map no longer exist, today's cartographers learn how to best display data, information, and the relationships between different data sets. Relationships that are difficult to show on a paper map may be more easily displayed on a computer display.
GIS has become the major tool for a wide range of applications. These include the analysis of phenomena and processes that affect our daily lives. Examples range from weather, politics, crime, real estate development, forest management and business decisions. The true power of GIS is its ability to combine and synthesize any form of geographic information.
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