A short Introduction to Data...

A short Introduction toData Visualisation

Pieterjan Robbe

Contents

1. General Introduction to Data- and Info Graphicswith historical overview

2. Examples of Good and Bad PracticeGraphical integrity

3. Consequences for Your Workwith pointers to technical software

I. General Introduction to Data- and Info Graphics

The Milestones Project

• Interactive overview of important events in the history of datavisualisation by Michael Friendly

http://www.datavis.ca/milestones/

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http://www.datavis.ca/milestones/

First Victory for Data Visualisation

John Snow, 1854

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Time Series

Planetary movements, 10th century

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Scales

Michael Florent van Langren, 1644

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1650-1700: First steps

• From 1650 onwards, more and more data becomes available inpolitics (wealth, population, agriculture) andeconomics (taxes, insurance)

• This increase causes a need for rigorous analysis techniquesbeyond the simple tabulated format⇒ visual thinking

• By 1700, many important data visualisation techniques such asmultivariate graphs, isolines and weather maps have beendiscovered• The two great inventors of modern graphical design are

• J. H. Lambert (1728-1777)• W. Playfair (1759-1823)

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William Playfair (1/3)

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Meanwhile in France

C. J. Minard, “Tableau Figuratif”, 1844

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1850-1900: The Golden Age

C. Lallemand, “L’abaque Triomphe”, 188510/33

II. Examples of Good and Bad Practice

click here for movie

https://www.bof.nl/2016/11/23/de-aivd-verbuigt-werkelijkheid-in-een-grafiek/

The Lie Factor

“Sometimes it is easier to see what has gone wrong. . .. . . than to explain how to do something right.”

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The Lie Factor

Lie factor =size of effect shown in graphic

size of effect in data(Tufte, 1983)

Common pitfails are

• apparent data size

• axis ranges

• incomplete data

• aspect ratio

• binning and ordering

Illustrations on the next slides!

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Apparent Data Size

Crude Oil Production in the USA (2011-2015)

2011 2012 2013 2014 2015

2011 2012 2013 2014 2015

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Apparent Data Size

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Axis Ranges

De Standaard Online, 3 september

188018901900191019201930194019501960197019801990200020102020

0102030405060708090

vrouwenmannen

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Axis Ranges

Metro, 21 september

2011 2012 2013 2014 2015 20160

50100150200250300350400450

diesel

benzine

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Incomplete Data

NUMA research output

2010 2011 2012 2013 2014 2015 2016 20170

10

20

30

40

year

num

bero

fjou

rnal

pape

rs

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Aspect Ratio

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Binning and Ordering

1 2 3 40

20

40

60

80

100

problem number

perf

orm

ance

1 2 3 40

20

40

60

80

100

problem number

perf

orm

ance

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The Bible of Data Visualisation

E. R. Tufte, The Visual Display of Quantitative Information, Graphics Press, Cheshire, CT, USA, 1983

Above all else show the data

Maximize the data-ink ratio

Erase non-data-ink

Erase redunant data-ink

Revise and edit

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Chart Junk

Laatste Nieuws, 17 augustus

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Minard Revisited

Napoleon’s Russian campaign in 1812

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Modern Data Visualisation

(from “Loren on the Art of MATLAB”, R2014b Graphics - Part 3)

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(from V. Coppé, D. Huybrechs, R. Matthysen and M. Webb, 2017)24/33


The chord map

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Jean-Luc Doumont and The Extreme

• Trees, maps and Theorems (2009)

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Tour de France

cumulative time of all riders of the Tour de France in 2013

7 000

−10 000

C. FroomeJ. Bakelants

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III. Consequences for Your Work

Guidelines

• Time spent on data visualisation is time well spent!

• Beware of data integrity

• Think about your graphic (use the 5 principles)

• Know your audience

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Outlook

π2

π 3π2

2π

−1

1

π2

π 3π2

2π

−1

1 sin(x)

sin(2x)

sin(3x)

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Outlook

100

101

102

103

104

105

41%15%

24%

24%

22%

50%0%nu

mbe

rof

sam

ples

original

reused

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Graphical Design

• Image aspect ratio, scale of the graphic

• Font font size, font type

• Lines line width, line color, line markers

• Legends do you need one? Where do you put it?

• Tables do you really need a graphic?

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Software Tools

• Small data sets (<1M points)

also PGFplots, Gnuplot. . .

• Large data sets (>1M points)

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References

E. R. Tufte, The Visual Display of Quantitative Information, GraphicsPress, Cheshire, CT, USA, 1983.

J. L. Doumont, Trees, maps, and theorems: Effective communicationfor rational minds, Principiae, 2009.

C. Chen, W. K. Härdle and A. Unwin, eds., Handbook of datavisualization, Springer Science & Business Media, 2007.

M. J. Kraak, Mapping time. Illustrated by Minard’s map of Napoleon’sRussian Campaign of 1812, Modern problems of geography andanthropology, Tblisi, Georgia, 2015.

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A short Introduction to Data...

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