What is GIS - mapping disease

In the mid 1800s Dr John Snow mapped the fatalities of a cholera outbreak in the Soho didtrict of London. He also took the time to understand the reasons for the anomolies in the mapping. Although nowdays such a mapping exercise would be undertaken in a GIS there are some important lessons to be gained by studying what John Snow did. His mapping in conjunction with his field research led him to conclude that the Broad Street was the source of the contamination. He petitioned for the pump handle to be removed and when it was the outbreak subsided. Although there is conjecture about whether or not the outbreak would have subsided on its own, the fact remains that a technique was born - a technique that some would say inspired todays GIS. To see the accompanying article be sure to visit http://learnpracticalgis.com/19th-century-public-health-map/