GIS stands for Geographic Information Systems. A GIS allows you to enter, query, view, and manipulate geographic information in the form of maps, photos, lists, and graphs. The GIS can contain many layers of information--subterranean, topographical, road atlas, electric lines, population density, etc.--for each location. Once this raw data has been entered into the database, that database can be queried to find answers to such complex questions as:

• How has the population changed over the past 10 years?
• How do I contain a diesel spill at a certain location?
• How has adding this stop sign affected traffic?