What is GIS?

A Geographic Information System, or GIS, is an organized collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyze, and display all forms of geographically referenced information.  In simple terms:  A Computer system capable to holding and using data describing places on the earth's surface to give you a better understanding of those places. 

Geographic Information System technology can be used for criminology, urban planning, evaluate environmental impact, identify the best location for a new facility, emergency response, and route planning.