The evolution of information visualisation

Visualisation has its historical roots as a way to convey data and as an aid for thinking; from the first maps drawn in the 12th century by the Chinese. The invention of Cartesian

coordinates in the 17th century and advances in the fields of mathematics paved the way for data graphics. Since the introduction of data graphics in the late 1700’s (Tufte 1983;

Cleveland 1993) visual representations of abstract information have been used to explore data and reveal patterns. Information visualisation has its origin with Lambert (1728-1777) and Playfair (1759-1823) who were the first to introduce graphics rather than simply presenting data in tabular form and can therefore be regarded as the inventors of modern graphics design (Tufte 1983; Tufte 2001).

Systematic visual representations replaced tables of numbers towards the end of the 18th century, after Playfair wrote the Commercial and Political Atlas in 1786 (Playfair 1786) and the Statistical Breviary, (Playfair 1801) which presented graphs and charts in a form that is easily understood by a modern reader. The statistical line graph, pie chart and bar chart; three of the four basic forms were invented by Playfair. Once Playfair had published these new graphical representations other writers began to contribute their own ideas about pictorial representation.

Joseph Priestly, (1733-1804) influenced by Playfair, was the first to create the concept of representing time geometrically. His revolutionary idea was the use of a grid with time on the horizontal axis; and the reigns of different monarchs represented by different length bars which granted instantaneous visual comparison. Similarly, the French physician Jacques Barbeu-Dubourg (1709–1779) and the Scottish philosopher Adam Ferguson (1723–1816) produced plots that followed a similar principle. In Dubourg’s case it was a scroll produced

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in 1753 that presented a complex timeline from the time of Creation to the present; Dubourg believed this period spanned 6,480 years. Ferguson published a timeline that begins at the time of the Great Flood (2344 BC—though indicating clearly that this was 1656 years after The Creation), and ranged across the births and deaths of all civilizations until 1780. James Playfair, a Scottish minister although no relation of William Playfair, published A System of Chronology, (Playfair 1784) in the style of Priestly time-bars.

During the 19th century, various forms of graphs, thematic maps and charts were developed. Florence Nightingale, for example, followed Playfair’s examples in order to convey statistical information to a wide audience. Nightingale produced Notes on Matters Affecting the Health, Efficiency and Hospital Administration of the British Army (1859), after witnessing the poor conditions in Crimea for soldiers that were injured (Nightingale 1859). For a variety of reasons this was an important publication but it is interesting from our point of view because it featured several graphs which she described as the “Coxcombs”1 (Figure 2.6) but which are more commonly known as polar area diagrams. The diagram is used to plot cyclical data (here monthly data are being compared) with each month taking 30 degrees of the circle. The size of the radius reports the size of the quantity of interest (In Nightingale’s diagram it is mortality statistics) and the separate shadings represent cause of death (the proportions taking up by the grey shading clearly demonstrate that most soldiers were dying from diseases caught whilst in hospital rather than wounds inflicted on the battlefield).

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Figure ‎2.6 A coxcomb chart

The association between mapping information and health statistics was pioneered when Dr. John Snow plotted cholera deaths during an outbreak in central London in 1854 (Figure 2.7). At the time it was widely thought that diseases like cholera were caused by ‘foul air’ but Snow was sceptical of this theory. After talking with Soho residents Snow deduced that the outbreak was centred on a water pump located in Broad Street and the disease declined after the pump was taken out of service. Later, when he was recording the case Snow simply marked the location of water pumps with crosses and deaths with dots on a map of the area.

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Figure ‎2.7 John Snow's Cholera Graphic

Shortly after the publication of Snow’s map the French engineer, Charles Joseph Minard produced what is commonly regarded as one of the best statistical graphs ever published (Tufte 1983; Wainer 2000; Friendly 2002). This graphic portrays Napoleon's losses suffered during his invasion of Russia in 1812 (Figure 2.8).

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The brown and black lines show Napolean’s army on its advance (brown) into Russia and then its later retreat (black). The thickness of the line shows the army’s size where it becomes clear that the army that arrived in Moscow was roughly a fifth the size of the one that began the march. The reader is able to follow the stylized geography because the map shows latitude and longitude and dates are shown at key points of the army’s movements. A temperature chart shows what the army had to endure, particularly during its retreat.

Although it is clear that Minard’s map is brilliant at conveying information about the Russian campaign it is not entirely clear why it achieves what it does achieve. In the following section, therefore, we attempt to discover what lies behind good graphic design.