Here is a data flow diagram that covers all the systems i will be describing

This is an overview of the system:

What is a GIS?

A geographical information system is any system that captures, stores, analyzes, manages, and presents data that are linked to any location.
http://en.wikipedia.org/wiki/Geographic_information_system

GIS allows us to view, understand, question, interpret, and visualize data in many ways that reveal relationships, patterns, and trends in the form of maps, globes, reports, and charts.
http://www.gis.com/content/what-gis

Journal

15/6/10: Created blog and added video for an introduction to GIS

Above is a short introduction to Geographical information systems. Enjoy :P