What is GIS
By adding the Latitude and Longitude to your database of things you can make a GIS map.
Even more exciting is the fact that once you've made that map you can go and search for information attached to that map.
You may want to find all the water fountains in your school yard or all the oak trees in your yard.
With GIS you can make a map that has both the water fountain list and the oak tree list, goto the map and ask it to display only the oak trees and the information on those trees.
The GIS map becomes a source of information and a map you can change depending on what you want to look for.