John Snow Cholera Map

“Broad Street” Cholera Outbreak 1854

John Snow Cholera Map Send an E-mail with the subject “John Snow Map” and we send a PDF version of the map (without the water mark) free of charge.

This poster is based on the map designed by John Snow, a physician in London, UK, in the year of 1854. During that year a cholera outbreak devastated the city of London, including the Soho district. More than 120 victims died during the first 3 days. Those days physicist thought that infections were caused by “bad air” (miasma), the germ theory (microorganism are causing infections) became widely accepted only a decade after.

John Snow being an early advocate of the germ theory did not have the means to actually proof the reason for the epidemic. So he approached the problem by using a map of the Soho district and marked each cholera case at the address. The more his data-set completed, the more it became obvious that the cholera cases form a cluster around one specific public water pump on Broad Street.

John Snow was able to convince the district council to remove the handle of that pump and subsequently the epidemic terminated. London water works had taken sewer polluted water from the river Thames for the Broad Street pump.

This print is based on a black and white scan of the map. planiglobe removed distortions, closed lines, put an explanatory text to the side and added color to the figure. The print is 60cm wide and 40cm high.