What is a Geographic Information System?

Basically, it's a way of interpreting maps and locations.... GPS uses a Longitude/Latitude based system for plotting points on the map, while others use proximity to local landmarks and sitings. Essentially, it describes a method with which to plot locations on a map.

a computer system that allows geographic information to be manipulated, so you can find, say, how many fire hydrants are more than 400ft from a main water line. it's not just about maps, although a GIS can create a map.

look it up on google or bing