What is GIS?

A Geographic Information System is a way of organizing and displaying information so that we can more easily understand our world. Basically, a GIS map brings together different layers of information about a place so that we can better understand that place. One layer could show where clam beds are located. Another could represent tidal flux. Yet another could display water quality.

Why is this layering so important? The power of a GIS over paper maps is that it allows you to view only the layers of information you want to see. It also allows you to compare these different pieces of information to better achieve your goals.