Every business that collects huge amount of data – be it geospatial data, transaction data, customer behaviour data, health diagnosis data, or any data that is related with lives of people in a region, is at the forefront of finding innovative solutions by leveraging the data insights using advanced data visualization techniques. One such solution was discovered by Dr. John Snow, a physician who used data visualization techniques to eliminate the root-cause for Cholera – an epidemic that broke out in the mid-19th century London and took more than a five hundred lives.
Confluence of Medical Science & Geospatial Data Visualization
During a cholera outbreak in the Soho district of London, in the August of 1854, 127 people died within three days, and all of them lived on or near Broad Street. By 10th September, 500 people in the area died and the mortality rate reached 12.8 percent. Dr. Snow ran chemical and microscopic examination of water from a public well water pump used by Broad Street dwellers to fetch water for household consumption, and he discovered that dirty well water consumption was the reason behind the deaths. The handle of the pump was dismantled resulting into containing the cholera deaths to significant measure.
Dr. Snow had later used dot density map to illustrate how the cholera deaths occurred around the well water pump. This was the first geographical analysis of a death data – plotting points on a map to look for relationships:
A dot map is a visual representation of a phenomenon in a geographic area. It shows spatial pattern based on a visual scatter. The dot map above shows cholera deaths that were reported during the outbreak. It is now clear that people who drank the water from Broad Street well water pump, contracted cholera, while others who didn’t, such as, workers in a brewery that had its own water supply, people living in a workhouse surrounded by cholera patients – but didn’t consume the any infected well water, and others. This helped Dr. Snow to validate his theory of dirty water being the root cause for the massive cholera outbreak.
He went ahead and created Voronoi Diagram to connect the incidence of cholera death with potential geographic sources and conduct an epidemiology analysis of the cholera breakout – the first of its kind, trying to evaluate the spread of cholera cases by factors in the nearby environment:
Voronoi diagram represents a plane partitioned into regions based on distance to selected points in a specific part of the plane. The set of points – cholera death incidence – is specified beforehand; for each point, there is a corresponding region consisting of all points closer to that point than to any other. These regions are called Voronoi cells. Voronoi diagrams are also called Thiessen Polygons.
Thiessen polygons are created by taking pairs of closely placed points and drawing a line that is equidistant between them and perpendicular to the line connecting them, so, all points on the lines in the diagram are equidistant to the nearest two (or more) source points. In the field of epidemiology, Voronoi diagrams or Thiessen polygons are used to correlate sources of infections in epidemics.
Problem-Solving & Innovation by Data Visualization
Both geographical analysis and epidemiology analysis provided strong validation in support of the theory established by Dr. Snow that cholera is a water-borne disease. Dr. Snow drew Thiessen Polygons around the infected water wells. Majority of cholera death incidents fell within the Thiessen polygon surrounding the Broad Street well water pump. The Thiessen polygons hence drawn further proved that most cholera deaths occurred within the shortest-travel-distance along streets to the infected water wells.
In today’s times of advanced data visualization tools that produce sophisticated statistical analyses visualizations, it is easier to map data with occurrences of business trends, and come up with value-added solutions that help business owners anticipate troubles, provide better services to their clients, and improve operational efficiencies.
Hashbrown Systems Expertise in Data Visualization
We, at Hashbrown Systems, have been working on one of the biggest Data Visualization undertakings for India. We mapped over 750 major, minor and negligible towns of the country and have created a tool that lets advertisers and marketers perform their job to their best.