Groundbreaking map of London's 19th century cholera outbreak digitised

22 April 2013

A student from the University of Southampton has digitised data from 19th century epidemiologist John Snow’s famous map of London cholera outbreaks, transferring the lifesaving information to modern day street layouts.

Snow plotted deaths from cholera in Soho in 1854 on a map. He found they were clustered around a water pump in Broad Street (now Broadwick Street). On the strength of his evidence, the handle of the pump was removed and the cholera outbreaks declined.

Postgraduate Geographer at the University of Southampton Robin Wilson says: “John Snow represented the deaths in each Soho street using rectangular blocks — the more blocks, the more cholera deaths which occurred at that location. It was a simple, but breakthrough way of visualising geographical clusters of disease, and ultimately saved many lives.”

Now Robin has brought Snow’s map into the 21st century by painstakingly geo-referencing every cholera death and pump location and transferring this to modern day maps of Soho, while also providing the digital tools for others to create their own versions.

“I have taken John Snow’s original data and digitised it, allowing it to be overlaid onto modern maps and analysed using modern methods. This should also allow some interesting ‘mashups’ to be created by others who are interested in interpreting Snow’s findings in a modern context,” he said.

Snow’s study was a major event in the history of public health and geography. In the 1850s, cholera was believed to be spread by ‘bad air’ and germs weren’t understood. His discovery helped change this and is widely regarded as the founding event of the science of epidemiology.

It is 200 years since the birth of John Snow and an exhibition is being held in London to commemorate his life:


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