Milestones in the History of Scientific -based scientific discoveries ?? Visualization • When have graphics led to scientific discoveries that might not have been achieved otherwise? ƒ Snow (1854): cholera as a water-borne disease ƒ Galton (1883): anti-cyclonic weather pattern ƒ E.W. Maunder (1904): sunspot cycle ƒ Hertzsprung/Russell (1911): temperature classes of stars (spectral type) ƒ Moseley (1913): concept of atomic number , York University ƒ Phillips (1958): “Phillips curve” --- inverse relation “Seeing Science”, AAAS, Boston, Feb. 18, 2008 between inflation and unemployment Slides: www.math.yorku.ca/SCS/Papers/aaas/ • In the history of graphs, what features led to these?

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Vignettes from the history of Context: Milestones Project www.math.yorku.ca/SCS/Gallery/milestone Topics: Themes: • Early graphical • Visual thinking & successes explanation • Sunspots: Galileo ĺ • Escaping flatland Maunder • Mapping the invisible • Graphic vision of Minard • Data ĺTheory ĺPractice • ISOs: Halley ĺ Galton • Graphical excellence • Galton’s greatest graphical discovery Project goals: • Comprehensive catalog of developments in history of data visualization • Tool to study themes, antecedents, influences, patterns, trends, etc. 3 4 Milestones: Content Overview Why the 1st statistical graph got it right Every picture has a story – Rod Stewart

c. 550 BC: The first world ? (Anaximander of Miletus) 1644: First visual representation of statistical data: determination of longitude between Toledo and Rome- Michel Florent van Langren, Spain 1669: First graph of a continuous distribution function (Gaunt's life )– Christiaan Huygens.

1801: Pie , circle graph - 1701: First contour map- Edmund Halley 1924: - 1991-1996: Interactive data visualization 1896: Bivariate map- systems (Xgobi, Jacques Bertillon ViSta) Actual distance=16o30’

Estimated distance

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Sorted by Authority

What else could he have done? Name Longitude Year Where Argelius, A. 28.0 1541 Brahe, T. 21.5 1578 Denmark Clavius, C. 26.5 1567 Germany Ianfonius, G. 17.7 1501 • What would occur to • … he could have Lantsbergius, P. 21.1 1530 Sorted by Priority Maginus, A. 29.8 1582 Italy men of his time to sorted by name, to Mercator, G. 19.6 1567 Flanders Year Name Longitude Where Organus, D. 30.1 1601 convey a message to 150 Ptolomeus, C. 27.7 Egypt show authority. Ortonius 26.0 1542 France 1471 Regiomontanus, 25.4 Germany Ptolomeus, C. 27.7 150 Alexandria 1501 Ianfonius, G. 17.7 Regiomontanus, I. 25.4 1471 Germany the king? 1530 Lantsbergius, P. 21.1 Schonerus, I. 20.8 1536 Germany 1536 Schonerus, I. 20.8 Germany Sorted by Longitude • … he could used a 1541 Argelius, A. 28.0 1542 Ortonius 26.0 France Longitude Name Year Where table have sorted by 1567 Mercator, G. 19.6 Flanders 17.7 G. Ianfonius 1501 1567 Clavius, C. 26.5 Germany • … he could have 19.6 G. Mercator 1567 Flanders year to establish 1578 Brahe, T. 21.5 Denmark 20.8 I. Schonerus 1536 Germany 1582 Maginus, A. 29.8 Italy sorted by longitude to 21.1 P. Lantsbergius 1530 priority (or show 1601 Organus, D. 30.1 21.5 T. Brahe 1578 Denmark 25.4 I. Regiomontanus 1471 Germany show the range. 26.0 Orontius 1542 France change). 26.5 C. Clavius 1567 Germany 27.7 C. Ptolomeus 150 Egypt 28.0 A. Argelius 1541 29.8 A. Maginus 1582 Italy 30.1 D. Organus 1601 7 8 Only a graph shows… Sunspots: Galileo ĺ Maunder

• central location • wide variability bias • • clustering, detached observations 1611: Galileo records movement of sunspots over time (Three letters on • name labels– avoiding overplotting sunspots, 1613)

range Visual ideas: •Animated graphic •“Small multiples” •Allows comparison •Self-explaining bias Actual distance=16o30’ A+ for info design! Estimated distance

See: Friendly, M., & Kwan, E. (2003). Effect Ordering for Data Displays. Computational Statistics and Data Analysis, 43(4), 509--539. 9 10

Scheiner: systematic recording Maunder: Butterfly diagram

1626: Christoph Scheiner invents helioscope & camera obscura to record sunspots (Rosa Ursina sive Sol , 1626-1630) 1904: E.W. Maunder plots distribution of sunspots in sun’s latitude by time • Discovery of 11-year sunspot cycles (& 22-yr: reversal of sun’s magnetic field)

11 12 Maunder: Butterfly diagram The graphic vision of C. J. Minard

1904: E.W. Maunder plots distribution of sunspots in sun’s latitude by time • Discovery of “Maunder minimum” (1645-1715): “Little Ice Age” • Smoothing reveals other extrema

• Marey (1878): “defies the pen of the historian in its brutal eloquence” • Tufte (1983): “the best statistical graphic ever produced”

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Why Minard? Visual thinking, visual explanation • Study breadth and depth of his work ƒ How related to work in his time? ƒ How related to modern ? 1840: Why did the bridge at ƒ How related to his personal history? Bourg-St. Andèol collapse? Minard’s report consisted essentially of this self-explaining Civil Engineer for ENPC diagram. (1810-1842) Visual Engineer for France (1843-1869)

15 16 Visual tools for state planning Flow as visual tools

Transport of passengers on the principal railroads in Europe in 1862 • 1830—1860: emergence of modern French state, dawn of globalization • Trade, commerce, transportation: ƒ Where to build railroads, canals? ƒ Visualizing changes over time, differences over space ƒ ĺ Flow maps and other graphical innovations

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Effect of US civil war on cotton trade The March Re-Visited (1869)

Before After Hannibal’s retreat

Napoleon’s 1812 campaign

19 20 Escaping flatland Halley: Mapping the invisible 3D maps & graphs from Halley to Galton

1701: Halley’s contour maps (an isogonic map: lines of equal 1701: Halley 1782: du Carla-Boniface 1866: Galton magnetic declination for the world) -- first thematic contour map of a data-based variable.

Visual ideas: • Smooth curves of equal value • Depicted an entire corpus of systematic & organized information • Theory of magnetism ĺ interpolated values where data missing 21 22

1817: Alexander von Humboldt (1769-1859) Germany Topo maps as 3D level-slices First graph of isotherms, showing mean temperature around the world by latitude and longitude.

1782: Marcellin du Carla-Boniface, longitude Visual ideas: France First topographical map, showing • average & smooth 70 contours of equal elevation. • suppress the map • moderating variable

Visual ideas: latitude • Contours: horizontal slices of a landscape 0 • Spacing indicates slope Recognizing that temperature depends more on latitude and altitude, a subscripted graph

shows the direct relation of altitude temperature on these two variables latitude

23 24 1879: Luigi Perozzo, Italy month Stereogram (3D population 3D maps Æ pyramid) modeled on pop actual data (Swedish Graphs census, 1750--1875)

Visual ideas: 1843: Léon Lalanne, France • Contour diagram of a table: • 3D stereogram temperature ~ hour x month

Construction for 3D surfaces Visual ideas: • Ordered table like a map • 3D level curves hour • 2D marginal projections • multiple views: , elevation, section

age 25 26 year

Galton’s discovery of the bivariate normal Visual smoothing Insight correlation surface (1886) Æ

27 28 Visual insight Æ Theory Galton’s discovery of weather patterns- Perhaps the most notable purely graphic discovery ever!

• Level curves are ellipses • Regression lines are loci of conjugate tangents

… that Galton should have evolved all this … is to my mind one of the most note- worthy scientific discoveries (Galton, 1863) arising from analysis of pure observation (Pearson 1920, Galton (1886, Pl X): Smoothed contours of heights of parents and children 29 30 p37)

Method: All weather stations across Europe asked to Visual abstraction Æ Patterns record data 3x/day for all of Dec., 1861 What varies with what, over time and space? Data: recordings of pressure barometric pressure, wind • mini, abstract maps: vars x TOD dir/speed, rain, temp., cloud: • iso-contours, to show 3x/day, 50 weather stations equivalence wind, rain in Europe. • arrows to show wind direction

temperature Graphic analysis: 3x31=93 maps, each with multivariate glyphs showing all variables AM noon PM

Data for Dec 5, 1861 Visual ideas: • Iconic symbols • Multivariate glyphs (stamps!) 31 32 The large picture Æ Insight Visual insight Æ Theory

AM12 PM Visual insight from 93 (3x31) Pattern: high-D graphs: Low pressure (black) in pressure • Changes in wind dir w/ early Dec. Æ CCW wind wind, rain pressure over time High pressure (red) in • Æ Winds revolve inwardly late Dec. temp. Æ CW wind (CCW) in low pressure areas– as in a cyclone; • Æ revolve outwardly (CW) in high pressure areas– “anti- cyclone”

Graphic: 3x3x31 grid, Theory: mapping {pressure, wind/ • Explained by Dove’s ‘Law of rain, temperature} x {AM, Gyration’ 12, PM} x day {1:31} • Prediction: reversed pattern (try this with your software!) (CW/CCW) in southern hemisphere – confirmed!

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Moseley’s discovery of atomic number Theory Æ 1913: Henry Moseley Practice of serial numbers of elements vs. square root of frequencies from X-ray spectra:

• linear relations Æ periodic table better explained by atomic number than weight (serial # must have a physical basis). • gaps in series Æ predicted existence of The first modern weather map, several undiscovered elements! London Times, Apr. 1, 1875 • multiple lines later explained with discovery of the spin of electrons.

Galton did for weathermen what Kepler did for Tycho Brahe. This is no The hallmark of good science is the small accomplishment. (Wainer 2005) discovery of laws that unify & simplify findings, and allow prediction of yet unobserved phenomena.

35 36 Graphs: Different strokes for different folks Conclusions Two roles for data visualization in science

• In the history of science, visualization often: ƒ … proved crucial in discovery ƒ … provided simple explanations for complex phenomena • Notable examples in this history illustrate … Wow! Ah ha! ƒ Importance of visual thinking ?? ƒ Interoccularity: message hits you between the eyes ƒ Role of smoothing in seeing patterns, gaining insight ƒ Necessity to escape flatland: Presentation Exploration & analysis • Progress in display of increasingly rich and complex data ƒ Data ĺ Visual abstraction ĺ Theory ĺ Practice Goal: the Wow! experience Goal: the Ah ha! Experience Single for a large audience Many , for a narrow audience 37 (you!), linked to analysis 38

Presentation graph: Nightingale (1857)

After reform Before reform

preventable

wounds

other

The best graphs pass the Interocular Traumatic Test: the message hits you between the eyes! 39