Tuesday, March 10, 2015

Maps in the Time of Cholera

As we approach the 201st birthday of British physician John Snow we can celebrate the occasion with a new interactive version of his famous Broadstreet Pump map.

In 1854 Snow plotted the deaths caused by cholera in the Soho area of London. The distribution of the dots helped Snow discover that cholera occurred most frequently among those who drank from the Broad Street water pump.

Kyle Walker's Broad Street Pump map overlays circular polygons over John Snow's original map. The polygons are scaled to show the number of cholera deaths recorded at each address. Kyle has created interactive map tiles from John Snow's original map, which means you can see Snow's own data on the map and and the locations of the neighborhood's water pumps.

If you want to create your own map from John Snow's data then have a look at Robin's Blog. Robin Wilson has mapped John Snow's data onto an Ordnance Survey map and also made the data available via Google Fusion Tables.

If you want to know more about how Kyle created his interactive John Snow map then have a look at his post on Using Custom Tiles in an RStudio Leaflet Map. The article explains how he created the map tiles from an image file of John Snow's original map using gdal2tiles.

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