GIS (Geographic Information Systems) is a collection of computer hardware, software, and geographic data for capturing, managing, analyzing, and displaying all forms of geographically referenced information.
GIS organizes geographic data as vector or raster layers on a map. Each layer has an associated database containing attributes for every graphic feature. This makes attribute queries and spatial queries very powerful. A user can search for all of the commercial land in a city (attribute query) and display those properties on the map. All properties within 100 feet of a river can also be selected (spatial query) and the user can analyze the associated database information.
This technology allows for tables from multiple databases to be joined together for enhanced queries and reports. For example, ownership and other property data from the county real estate system can be tied to the parcel layer. The ability to integrate data from a variety of sources enhances the analysis users can perform and saves time by having the information in one application.