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What is a Geographical Information System?

M. McGee
M. McGee

A geographical information system can be many different things. At its core, it is any method of cataloging, monitoring or utilizing geographic information for a specific purpose. This could literally be anything from using the ground’s shape to predict weather patterns to finding property lines to navigating in the woods with a global positioning system (GPS). The current most common meaning for a geographical information system is a computer-based model of a specific area of real-life terrain. These systems typically contain non-geographic information related to the land they cover.

The modern geographical information system came into being during the 1960s. The Canadian Department of Forestry and Rural Development developed the Canada Geographic Information System (CGIS) to catalog rural areas of the Canadian wilderness. They wanted these maps to show not only topographic information, but also additional data relating to plant and animal life in those areas. Since this level of interactive detail was difficult with paper maps, a computer system was used in their place.

Man holding computer
Man holding computer

The majority of the work that goes into a geographical information system is actually entering the data. Since the information in the system is representative of real places, it is important that the information is both accurate and up to date. This means that any information entered into the system needs to either come from a verified source or be checked against multiple existing sources for accuracy.

The data entered into a geographical information system typically comes from one of three sources. For current systems, many governments keep basic geographic information in publicly accessible databases. When such information isn’t available, local maps are often scanned and digitally entered into the systems. The last common method is through global information systems such as the Global Navigation Satellite System or GPS. These systems use digital information by default, so they can often enter their data directly into databases.

The current increase in web-based mapping sites has created a change in the way people look at geographical information systems. These web-based applications, such as Google Maps, have free and open geographic information available to anyone that wants it. Through a standard application programming interface, it is possible to use the data in these web systems to create individual geographic systems. Since the mapping happens outside of the program, updates to the web maps also update the program.

The prevalence of the publicly accessible geographical information systems, coupled with publicly available governmental records, has created its share of controversy. Through mash-up mapping programs, it is possible to single out areas that have disproportionately high or low crime, education rates or income. Many watchdog groups feel that this level of accessibility was not the original intent of these systems and have begun taking steps to have them legislated more closely.

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