A geographic information system (GIS) is a database system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data. A large portion of this data is spatial in nature. This means that the data is referenced to the Earth’s surface with regard to a specific coordinate system.
Combined with the spatial data is tabular data known as attribute data. Attribute data can be generally defined as additional information about each of the spatial features.
When these two data types are brought together, a GIS is enabled to be an effective spatial analysis tool.