The Broad Street water pump.
A closer look at the compass rose used on the map.
Dr. John Snow's cholera map (1854)
Dr. John Snow created a map of Soho to illustrate how the cholera outbreak of 1854 was centred around the water pump in Broad Street. By plotting the locations of those who contracted cholera on a map, Dr. Snow was able to demonstrate the significance of the Broad Street water pump to the outbreak. The strength of his map and other statistical studies was enough to convince the council to disable the water pump in Broad Street. For many, Snow's work at this time is considered to be one of the most significant early examples of epidemiology.
The map here is a recreation of Dr. John Snow's original for use in a children's book covering the subject.
By using two contrasting colours, a strong red on a neutral background, it is possible to quickly see the distribution of cholera cases. It is also evident to see how strong Dr. Snow's argument would have been in terms of the connection between the Broad Street pump and the cholera outbreak.