This is the second chapter of the series of contents dedicated to the cholera map, created by Dr. John Snow during an epidemiological outbreak that killed hundreds of people within a week in 1854 in the Soho region of London. The previous chapter was The situation in the cities.

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Proximity sensitivity

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Cities densely occupied by people without resources, at a concentration that was 4x that of Manhattan today, led to disease outbreaks.

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In addition to its intensity, the Soho outbreak had its own geographical feature, this was the region where Dr. John Snow lived.

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Presumably he knew some of the people who died.

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Especially because the outbreak was more intense in poor regions, but it reached the immediate vicinity of the middle and upper classes.

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Buckingham Royal Palace itself is a short distance from the focus.

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A few years earlier, an even more intense outbreak had struck the Lambeth region, which is located to the south, on the other bank of the Thames, without giving the same importance.

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Just take a look at the cover of the book to get an idea of how poor and desolate this region was at the time.

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The miasma theory did not allow the association of factors between the outbreaks, attributing all the danger to toxic air.

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As the first law of Geography, formulated by Waldo Tobler, says:

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All things are related to everything else, but close things are more related than distant things

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If the causes of the disease could not yet be associated, there was a close relationship between those affected and Dr. Snow.

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At that time John Snow was considered a medical prodigy, although relatively young, he accumulated long years of dedication to medicine.

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His work in anesthetic procedures for pain relief and the recognition he received after attending Queen Victoria's delivery gave him high prestige in the community.

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In spite of everything, he was a simple and accessible person.

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The Broad Street region, the epicenter of the outbreak, was 600 meters from his residence on Sackville Street and it is very likely that he frequented commercial establishments there.

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As the deaths accumulated, 127 in three days, 500 in one week, he went to the region in search of answers.

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There he found a figure who played a key role in the investigations, Reverend Henry Whitehead, pastor of the region and knowledgeable about the families that had been victims of the disease.

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Thinking about current methods, Reverend Whitehead was the database, he had the list of addresses of the deceased, something like the CRM of that phenomenon.

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It was he who identified the places where the deaths were concentrated and this concentration occurred in the Broad Street region.

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We can consider that the work of Dr. John Snow and Reverend Henry Whitehead was the first import of data for maps in history.

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They performed this feat so that they could visualize the deaths point by point and understand their geographical distribution.

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But that was not yet the moment when the famous map was produced, at this point a few doodles were enough on the map to make them notice the concentration.

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The famous map would be created to convince the parish administration of the discoveries they had made and the consequent need to ban the Broad Street bomb.

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That's the subject of the next chapter, Not everything is as it seems.

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Today you can carry out such powerful analysis using the feature of Data mapping, available in Personal and Professional plans.

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