A Short History of Data Visualisation
By: Richard Farnworth
Tags: Data Science, Visualization, Graphic Design, Charts, Data Visualization

A Short History of Data Visualisation

With modern technology, visualising data has never been easier. A few clicks of the mouse, can more or less instantly turn a huge table of raw numbers into a visually appealing and easy to interpret diagram. Graphing data provides a high-speed shortcut to creating understanding and getting your point across.

Many of the visualisation techniques of today were invented during the industrial revolution, with the field making large strides in the mid-19th century. What may seem simple and obvious today, such as a bar chart or line graph, would have been strange and unfamiliar to someone 200 years ago. In this article we take a look at some of the major innovators in the graphical representation of data and some of their famous works.

Map-makers

Ptolemy’s world map — Source: Wikipedia

Arguably the first data visualisations were in the field of Cartography. Originally used for the purposes of navigation, land ownership and general human curiosity, maps have been around in some form or another for at least ten thousand years. In ancient times, information about the world, collated from eyewitness accounts (and a fair amount of guesswork) would be engraved into stone or clay. Over the centuries, instruments such as the compass (200 BC) and sextant (1731) allowed for more precise measurements and increasingly accurate maps, with the printing press enabling their mass production.

In 1569, the Flemish cartographer Gerardus Mercator’s map of the world marked a major development in how we depict the surface of the spherical Earth on a flat piece of paper.

In his Mercator Projection, local geography is preserved and straight lines on the map translate to lines of constant bearing when looking at a compass, making it ideal for navigation at sea. It proved popular, with several hundred copies of the original being printed and is still the most common world map projection we see today.

William Playfair

William Playfair has a pretty eclectic CV. In a meandering career, unthinkable today, he turned his hand to espionage, engineering (as PA to James Watt, of steam engine fame), drafting, accounting, inventing, metalwork, investment broking, economics, translation, publicity, land speculation, banking, blackmail and journalism. During the French Revolution he worked as a spy for the British government, ran a currency counterfeiting operation to collapse the French currency and took part in the storming of the Bastille. A bit of a rogue and a scoundrel he also ended up in debtors’ prison after several failed businesses. However, his lasting legacy is in the field of statistics, with the charts he designed forming the core of data visualisation today.

In Playfair’s day, data were typically displayed in dry tables, presented with little thought for their interpretation. If you wanted to understand something, there were no intuitive shortcuts, only the laborious task of poring back and forth through the numbers, remembering, copying and comparing figures as you went.

Then, in 1765, along came the above timeline chart from Joseph Priestley, showing the overlapping lifetimes of various classical statesmen and philosophers. Rather than just listing names, birth-years and death-years, Priestley plotted them on a timeline, making it immediately obvious which historical figures were contemporaries. These timelines proved a success and directly inspired Playfair’s invention of the bar chart, first appearing in his Commercial and Political Atlas.

William Playfair — Commercial and Political Atlas — Source

The chart shows the balance of trade for Scotland with various territories in Europe and the New World. By presenting data this way, it’s easy to spot Scotland’s strong economic links with Ireland and its trade imbalance with Russia.

For England, he had more data available and was able to produce time-series charts, showing how the balance of trade shifted over time. These charts were skilfully and painstakingly engraved into metal printing plates and copied by spreading ink into the recesses before pressing paper against them. It’s thought that on early reproductions, Playfair may have hand-coloured the charts himself. We have it pretty easy these days!

William Playfair — Commercial and Political Atlas — Source

Fifteen years later, he was at it again, this time with the sometimes controversial pie chart and various creative combinations. It’s astonishing to think, that more than two hundred years later, the ideas of one man still make up the bulk of the chart options in state of the art data visualisation software.

William Playfair — proportion of the Turkish Empire which falls in Asia, Africa and Europe — Source

Charles Joseph Minard

A few decades later, emerged a French civil engineer who made significant innovations in combining the fields of statistics and cartography.

In 1845 he created a “flow map” of the area around Dijon (of mustard fame) and Mulhouse in eastern France, displaying traffic data collected on roads through the area. This was distributed to dozens of stakeholders ahead of routing a new railway line through the area. Perhaps as a result of these maps, the modern day rail network roughly follows the lower dark line through Dole, Besançon and Belfort.

Charles Joseph Minard — road traffic between Dijon and Mulhouse — Source

He’s most famous however for his depiction of Napoleon’s disastrous invasion of Russia in 1812. His flow diagram below graphically depicts the depletion of Napoleon’s armies from almost half a million to virtually nothing as it trudged, froze and starved its way to Moscow and back. It’s a stark illustration of the failure of the campaign and its human toll. These types of diagram are now commonly referred to as “Sankey charts”.

Chales Joseph Minard — map of Napoleon’s Russia campaign — Source

Florence nightingale

The rightly venerated founder of modern nursing, was also a talented mathematician who was a pioneer in the graphical representation of statistics. Building on the ideas of Playfair, she incorporated charts into many of her publications and is credited with the invention of the Polar Area Chart, or “Coxcomb”.

“Diagram of the causes of mortality in the army in the East” — Source: Wikipedia

The chart depicts the different causes of death by month in the Crimean War, with the area of each wedge representing the size of the statistic. This type of chart lends itself well to cyclical data, although in this case Nightingale provided separate charts for the two years she covered.

Nightingale made several studies of the sanitary conditions in Crimea, India and the UK, and used charts like the above in lobbying for reform. Her work had great influence on the Public Health Act of 1875, which is credited by some as increasing the life expectancy in the UK by 20 years.

Francis Galton

The scatter plot is a mainstay of bi-variate analysis and there is no one person who can be claimed to be the inventor. One person who comes close however is the Victorian era statistician Francis Galton. A prolific writer and scientist, his contributions to the field statistics are immense, although now somewhat controversially due to his connection to eugenics.

In analysing the relationships between two variables, Galton devised a graphical technique where frequencies of each combination are plotted on a grid. Over this grid, contour lines are overlaid, showing the density of the data. For two correlated, normally distributed, variables, these contours should form an ellipse with the long axis acting as a form of linear regression.

A comparison of adult children’s heights, vs the average of their parents. Source: http://euclid.psych.yorku.ca/SCS/Gallery/images/galton-corr.jpg

The Information Age

Things progressed fairly slowly in the first half of the twentieth century, but then came the advent of computers. In 1981, the Xerox 8100 Star introduced the first commercial Graphical User Interface (GUI), and with it, applications like spreadsheets with the ability to automatically generate graphics from tables of information. What once took hours of careful etching or drawing could be done with a few clicks of the mouse, along with added ease of editing, formatting and updating. From there, the variety of charting techniques and styles has exploded, with countless software packages offering an array of methods for presenting your data.

Honorable mentions

Charles Dupin: Created the earliest known Chloropleth map, plotting illiteracy rates across France in 1826.

Charles Dupin — Carte figurative de l’instruction populaire de la France, 1826

John Snow: Mapped the Broad Street Cholera Outbreak of 1854 using a dot map, showing that the disease was spread via contaminated water, rather than the air as previously thought.

Mary Eleanor Spear: Developed the box plot in 1952 in her book Charting Statistics after working as a graphical analyst in the US civil service.