A geographic information system (GIS) is a computer system for capturing, storing, checking, and displaying data related to its location.
GIS can show many different kinds of data on one map. This enables people to more easily see, analyze, and understand patterns and relationships.
With GIS technology, people can compare the locations of different things in order to discover how they relate to each other.
For example, using GIS, the same map could include sites that produce pollution, such as gas stations, and sites that are sensitive to pollution, such as wetlands. Such a map would help people determine which wetlands are most at risk.