A computer-based tool used to gather, transform, manipulate, analyze, and produce information related to the surface of the earth. This data may exist as maps, three-dimensional models, tables, or lists. A GIS can be as complex as a whole system that uses dedicated databases and workstations hooked up to a network, or as simple as off-the-shelf desktop software. Transportation agencies use GIS for a variety of infrastructure management purposes including mapping and location identification, spatial analysis, presentation, and reporting of inventory and other useful information. The GIS is an important data integration tool for Asset Management because every asset can be tied or referenced to a particular location on a highway map and analyzed using GIS software (see location reference system).