What is a Geographic Information System (GIS)?  A GIS is a specific piece of computer software that, like a database program, allows the user to store, maintain, analyze, and display database information.  What makes a GIS different from other database systems is that the information managed has a geographic or spatial context.  Based on the common denominator of geographic location, GIS ties data from many different sources into one common map form.  This allows the user to visualize the data and see how the different data interact, resulting in a better understanding of the information and a more informed decision process.