Common visualization Issues & how to fix them Duen Horng (Polo) - - PowerPoint PPT Presentation

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Common visualization Issues & how to fix them Duen Horng (Polo) - - PowerPoint PPT Presentation

Feb 14, 2024 575 likes •1.23k views

http://poloclub.gatech.edu/cse6242 CSE6242 / CX4242: Data & Visual Analytics Common visualization Issues & how to fix them Duen Horng (Polo) Chau Assistant Professor Associate Director, MS Analytics Georgia Tech

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http://poloclub.gatech.edu/cse6242


CSE6242 / CX4242: Data & Visual Analytics


Common visualization Issues &
 how to fix them

Duen Horng (Polo) Chau


Assistant Professor
 Associate Director, MS Analytics
 Georgia Tech

Partly based on materials by 
 Professors Guy Lebanon, Jeffrey Heer, John Stasko, Christos Faloutsos

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Student of 
 Edward Tufte

http://a.co/6BhlPfZ

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Edward Tufte

An American statistician and professor emeritus of political science, statistics, and computer science at Yale University. He is noted for his writings

  • n information design and

as a pioneer in the field of data visualization.

  • Wikipedia
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Also Highly Recommended:

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Can you improve its visual design?

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Which is better?

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What can you improve?

Tables

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What’s the problem with making everything 
 bold or italic?

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http://www.youtube.com/watch?v=A8I9pYCl9AQ

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“When everyone is super, 
 no one is super”

http://www.youtube.com/watch?v=A8I9pYCl9AQ

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“When everyone is super, no one is super”

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A lot of “chart junk”. 
 Low “data to ink” ratio (Edward Tufte)

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Higher “data to ink” ratio

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Problems?

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The color scheme reminds you of what?

Bar Charts

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Better than Christmas


(Use color brewer to find good color schemes)

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Company Profits

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Don’t show profits in red!!
 Think carefully about your color choices.

Company Profits

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Misleading Bar Charts

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Vertical axis of bar charts 
 should start at 0, almost always

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Disorienting color bars

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Use gradation

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Avoid Tilted or Rotated Labels

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Bars Can be Horizontal

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Bars Can be Horizontal

When labels are hard to read, try horizontal layout. Don’t settle for the default.

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25 http://www.apple.com/imac/performance/

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Line Charts (a.k.a. fever lines)

Can you improve the tick labels?

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Use ticks at common intervals (e.g., 2, 5, 10, etc.)

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Note y-axis does not need to start at 0. 
 Why not as bad as in the case of bar chart?

Too flat or too steep?

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Rule of Thumb

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Multiple Patterned Lines 
 in one chart

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Which one is more effective? Why? 
 What if you have many lines you want to show?

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“Small Multiple” - Edward Tufte
 Better than overlapping (sometimes)

“a series or grid of small similar graphics or charts, allowing them to be easily compared”

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The Dreaded Pie Charts

Why people like to use pie charts?

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34 http://www.wired.com/2008/02/macworlds-iphon/

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35 http://flowingdata.com/2012/06/15/what-3-d-pie-charts-are-good-for/

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36 http://wonkette.com/412361/all-193-of-republicans-support-palin-romney-and-huckabee

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38 http://infosthetics.com/archives/2008/09/funniest_pie_chart_ever.html

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Log scale instead of linear scale

Include numbers from different orders of magnitude

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Example

log-log

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Example

“log” also works well for time

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In-class Exercise.

Applying what you have just learned.

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How to fix the defaults

43 http://www.darkhorseanalytics.com/blog/clear-off-the-table

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How to fix the defaults

43 http://www.darkhorseanalytics.com/blog/clear-off-the-table

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Great Work destroyed by
 Poor Presentation

Bad color schemes Bad, tiny fonts Too much animation Too much data

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100 times faster!

http://www.youtube.com/watch?v=lpvgfmEU2Ck&feature=player_embedded

Don McMillan: Life After Death by PowerPoint

can you read this?

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Practitioners’ Guide

Colors: start with black & white Forces you to focus on content and layout Then add colors, carefully Fonts: sans-serif generally easier to read On Mac: Helvetica is great start On Windows: Arial? Animation: start with no animation, then add meaningful ones

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Practitioners’ Guide: Use Pictures and Videos

“Pictures” include tables, diagrams, charts, etc.

  • Pictures often more succinct & memorable
  • People like pictures and love movies

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And show them ASAP! 


Once people fall asleep, it’s hard to wake them up! If you have good stuff, show them now.

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Example

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Practitioners’ Guide: Additional Tips for PhD students / Researchers

Crown-jewel pictures are important

  • Overview of what readers is going to get — cut to the

chase

  • People skim; look at “interesting” things first
  • Reviewers are busy and sleepy 😵 (read 5-10 papers per

conference) — it’s refreshing to read an interesting paper How to do it?

  • Use your most impressive figure
  • Can be similar to another shown later

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Figures should be self-contained.

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http://www.cs.cmu.edu/~dchau/polonium_sdm2011.pdf

Example

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Figures should be self-contained

Why?

  • Don’t make people go back

and forth between text & figure

  • Bad figures means bad first

impression (reject!) How to fix?

  • Succinctly describe your

main (take-away) messages 


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Example

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Use legible fonts.

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For printed materials, print them out and check! Rule of thumb: about 7 lines of text on a slide.

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If people can’t see it, they won’t appreciate it.

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Apple UI Design Guidelines

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https://developer.apple.com/design/tips/

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Example

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Higher is better. Apolo wins.

* Statistically significant, by two-tailed t test, p <0.05

Judges’ Scores

8 16

Model- based *Prototyping *Average

Apolo Scholar

Score

Example