Information Visualization Crash Course
Chad Stolper Assistant Professor Southwestern University
(graduated from Georgia Tech CS PhD) 1(AKA Information Visualization 101)
Information Visualization Crash Course (AKA Information - - PowerPoint PPT Presentation
Information Visualization Crash Course (AKA Information Visualization 101) Chad Stolper Assistant Professor Southwestern University (graduated from Georgia Tech CS PhD) 1 What is Infovis? Why is it Important? Human Perception Chart Basics
Information Visualization Crash Course
Chad Stolper Assistant Professor Southwestern University
(graduated from Georgia Tech CS PhD) 1(AKA Information Visualization 101)
What is Infovis? Why is it Important? Human Perception Chart Basics
(If Time, Some Color Theory)
The Shneiderman Mantra Where to Learn More
2What is Information Visualization?
4Information Visualization
“The use of computer-supported, interactive, visual representations of abstract data to amplify cognition.” Card, Mackinlay, and Shneiderman 1999
5Communication Exploratory Data Analysis (EDA)
6Communication
7(gone wrong)
Edward Tufte
An American statistician and professor emeritus of political science, statistics, and computer science at Yale University. He is noted for his writings
as a pioneer in the field of data visualization.
Space Shuttle Challenger
January 28, 1986
10What happened?
Morning Temperature: 31°F
https://www.youtube.com/watch?v=6Rwcbsn19c0
How did this happen?
15Morton Thiokol’s Presentation
16So, communication is extremely important.
Visualization can help with that – communicate ideas and insights.
31Visualization can also help with Exploratory Data Analysis (EDA)
But why do you need to explore data at all???
33“There are three kinds of lies: lies, damned lies, and statistics.”
35Mystery Data Set
36Mystery Data Set
Property Value mean( x ) 9 variance ( x ) 11 mean( y ) 7.5 variance ( y ) 4.122 correlation ( x,y ) 0.816 Linear Regression Line y = 3 + 0.5x
37Anscombe’s Quartet
43https://en.wikipedia.org/wiki/Anscombe%27s_quartet
Anscombe’s Quartet Sanity Checking Models Outlier Detection
44Anscombe’s Quartet Sanity Checking Models Outlier Detection
45Anscombe’s Quartet Sanity Checking Models Outlier Detection
46Anscombe’s Quartet Sanity Checking Models Outlier Detection
47Data visualization leverages human perception
49Name the five senses.
51Sense Bandwidth (bits/sec) Sight 10,000,000 Touch 1,000,000 Hearing 100,000 Smell 100,000 Taste 1,000
http://www.britannica.com/EBchecked/topic/287907/information-theory/214958/PhysiologyA (Simple) Model
A (Simple) Model of Human Perception
Parallel detection of basic features into an iconic store Serial processing
identification and spatial layout
Stage 1 Stage 2
54Stage 1: Pre-Attentive Processing
Rapid Parallel Automatic
(Fleeting = lasting for a short time)
55Stage 2: Serial Processing Relatively Slow (Incorporates Memory) Manual
56Stage 1: Pre-Attentive Processing
The eye moves every 200ms
57Stage 1: Pre-Attentive Processing
The eye moves every 200ms (so this processing occurs every 200ms-250ms)
58Example
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59Example
1281768756138976546984506985604982826762 9809858458224509856458945098450980943585 9091030209905959595772564675050678904567 8845789809821677654876364908560912949686
60A few more examples from
Left Side Right Side
Left Side Right Side
Raise your hand if a RED DOT is present…
64Color (hue) is pre-attentively processed.
67Raise your hand if a RED DOT is present…
68Shape is pre-attentively processed.
71Determine if a RED DOT is present…
72Hue and shape together are NOT pre-attentively processed.
75Pre-Attentive Processing
Stephen Few “Now You See It”
Pre-Attentive à Cognitive
78Gestalt Psychology
Berlin, Early 1900s
79Gestalt Psychology
Goal was to understand pattern perception
Gestalt (German) = “seeing the whole picture all at once”
Identified 8 “Laws of Grouping”
80http://study.com/academy/lesson/gestalt-psychology-definition-principles-quiz.html
Gestalt Psychology
How many groups are there?
82Proximity
84How many groups are there?
85Similarity
87How many shapes are there?
88Closure
90How many items are there?
91( ) { } [ ]
92( ) { } [ ]
Symmetry
93How many sets are there?
94Common Fate
How many objects are there?
97Continuity
99How many objects are there?
100Good Gestalt
102What is this word? (Please Shout)
103Past Experience
Past Experience
Pre-Attentive Processing Gestalt Laws
107Detect Quickly
108Detect quickly does NOT mean
detect accurately
Ideally you want both.
109Positions Rectangular areas
(aligned or in a treemap)
Angles Circular areas
Crowdsourced Results
1.0 1.5 2.0 2.5 3.0 T1 T2 T3 T4 T5 T6 T7 T8 T9Log Error
Positions Rectangular areas (aligned or in a treemap) Angles Circular areasMore accurate Less accurate
I I
PositionIMll
1 I
LengthF-l
Iha I
I0.I
I I
Volumerl
l¶kJ ColorAn example analysis for area perception is shown in Figure 16. The top line shows that a series of decreasing areas can be used to encode a tenfold quantitative
randomly, making it more difficult to judge the relative sizes of different areas accurately (hence, area is ranked fifth in Figure 14). Nevertheless, small mis- judgments about the size of an area only leads to small misperceptions about the corresponding quantitative value that is encoded. The middle line shows that area can encode three ordinal values. However, one must be careful to make sure
ACM TransactionsMackinlay, 1986
112Stephen Few “Now You See It”
What does this tell us?
114Barcharts, scatterplots, and line charts are really effective for quantitative data
20 40 20 40 20 40 20 40 20 40
115(and for statistical distributions) Tukey Box Plots
119Median Outliers Largest < Q3 + 1.5 IQR Smallest > Q1 - 1.5 IQR Largest < Q3 Smallest > Q1
120Tufte’s Chart Principles
122Edward Tufte
Tufte’s Chart Principles
DO NOT LIE!
Maximize Data-Ink Ratio Minimize Chart Junk
125Tufte’s Chart Principles
DO NOT LIE!
Maximize Data-Ink Ratio Minimize Chart Junk
126http://www.perceptualedge.com/blog/?p=790
12910 20 30 10 20 30 10 20 30 10 20 30 10 20 30
131Tufte’s Chart Principles
DO NOT LIE!
Maximize Data-Ink Ratio Minimize Chart Junk
132Please…
135No pie charts. No 2.5D charts.
13637 36 24 2 1
1385 10 15 20 25 30 35 40
139PLEASE DON’T EVER DO THIS!
14110 20 30 40
142Two times to use a pie chart…
14350-50
14475-25
145But otherwise…
146Barcharts, scatterplots, and line charts are really effective for quantitative data
20 40 20 40 20 40 20 40 20 40
147Anyone else bored by my color choices?
148In fact, grayscale can be risky…
149In fact, grayscale can be risky…
150Color is Powerful
151Call attention to information Increase appeal Increase memorability Another dimension to work with
Color
152How many of you have heard of RGB?
153We see in RGB, but we don’t interpret in RGB…
155How many have heard of HSV?
156HSV Color Model
Hue/“Color” Saturation/Chroma Value/Lightness
157Hue
Post & Greene, 1986
159Hue
http://blog.xkcd.com/2010/05/03/color-survey-results/ 160Hue and Colorblindness
10% of males and 1% of females are Red-Green Colorblind
162Color and Quantitative Data
Gray scale Single sequence part spectral scale Full spectral scale Single sequence single hue scale Double-ended multiple hue scale 169Color and Quantitative Data
Can you order these (lowàhi)?
170us
Binary Diverging Categorical Sequential Categorical Categorical
http://www.personal.psu.edu/faculty/c/a/cab38/ColorSch/Schemes.html via MunznerColor Scales
Color Brewer
http://colorbrewer2.org/
172Overview Zoom+Filter Details on Demand
Shneiderman Mantra (Information-Seeking Mantra)
173http://visual.ly/every-single-death-game-thrones-series
176Where to learn more?
185CS 7450 Information Visualization Every Fall
186Visualization @GeorgiaTech
vis.gatech.edu
187How to Make Good Charts
– http://www.edwardtufte.com/tufte/courses
Information
– http://www.edwardtufte.com/tufte/books_vdqi
Designing Tables and Graphs to Enlighten
– http://www.amazon.com/Show-Me-Numbers- Designing- Enlighten/dp/0970601972/ref=la_B001H6IQ5M_1_ 2?s=books&ie=UTF8&qid=1385050724&sr=1-2
188Visualization Theory “Books”
– http://www.cs.ubc.ca/~tmm/talks.html – http://www.cs.ubc.ca/~tmm/vadbook/
– http://www.amazon.com/Information-Visualization-Perception-Interactive- Technologies/dp/1558605118
– http://www.amazon.com/Now-You-See-Visualization- Quantitative/dp/0970601980/ref=pd_bxgy_b_img_z
– http://www.edwardtufte.com/tufte/books_ei
– http://www.edwardtufte.com/tufte/books_visex
– http://www.edwardtufte.com/tufte/books_be
– http://www.amazon.com/Visualization-Analysis-Design-AK- Peters/dp/1466508914
189Perception and Color Websites
– http://www.csc.ncsu.edu/faculty/healey/PP/index.h tml
– http://colorbrewer2.org/
Workshops)
– http://www.stonesc.com/color/index.htm
NASA
– http://blog.visual.ly/subtleties-of-color/
190Visualization Blogs
– http://flowingdata.com/
– http://infosthetics.com/
– http://www.informationisbeautiful.net/
– http://blog.visual.ly/
– http://thisisindexed.com/
191Infographics
Visual.ly/view
(wtfviz.net)
192Thanks!
Chad Stolper
chadstolper@gatech.edu
193Questions?
Chad Stolper
chadstolper@gatech.edu
194 thisisindexed.com Jessica Hagy