While John Snow is recognized as a pioneer in the area of modern epidemiology, he made his name with the use of maps and what can be described as the first application of Location Intelligence.
Born in 1813 in the UK, John was a physician by trade but had a very high aptitude for math. Cholera was a major illness throughout the 19th century, and Snow had treated many patients in his hometown before moving to London. His experience made him skeptical of the common theory that the disease was airborne, believing that it was the result of ingestion of contaminated water. In 1854 a major outbreak occurred near his London home, which prompted him to map the location of the deaths.
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At first he noticed that while there were many deaths within a defined area, there were also anomalies like the workhouse (jail) and brewery that had none. The fact that both had private water supplies, and that he had learned that fermentation killed the bacteria, helped him to refine his argument. Since most homes relied on public wells for water he added pumps to the map and saw the pattern emerge around a pump located at Broad Street. He then interviewed people whose families experienced deaths closer to other pumps and found they had all used the Broad Street pump for various reasons.
Snow was able to convince local authorities to remove the handle on the Broad Street pump, after which deaths started to immediately decline. However, his theory was still just that as he could not find bacteria in the water, until Reverend Henry Whitehead, who was actually looking to discredit it, came across the insight needed to make the case. He learned that one of the early deaths from Cholera was an infant who lived steps from the pump, and upon interviewing his mother learned of their leaking cesspool and how she had unknowingly washed the babies diapers above the well.
Ultimately John Snow triumphed but not until after his death in 1858. Following his death his contributions to science were widely recognized and celebrated, but not necessarily for Location Intelligence. Beyond receiving many awards, a pub called the John Snow now stands where the original pump was located on Broad Street, and important POI for any GIS professional!
http://www.ph.ucla.edu/epi/snow.html
http://www.ph.ucla.edu/epi/snow/snowmap1_1854.html
http://www.ph.ucla.edu/epi/snow/snowmap2_1854.html
https://en.wikipedia.org/wiki/John_Snow