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

▶
common visualization issues how to fix them
SMART_READER_LITE
LIVE PREVIEW

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

Feb 19, 2024 369 likes •952 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

slide-1
SLIDE 1

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

slide-2
SLIDE 2

2

Student of 
 Edward Tufte

slide-3
SLIDE 3

3

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
slide-4
SLIDE 4

Also Highly Recommended:

slide-5
SLIDE 5

5

Can you improve its visual design?

slide-6
SLIDE 6

6

Which is better?

slide-7
SLIDE 7

7

What can you improve?

Tables

slide-8
SLIDE 8

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

slide-9
SLIDE 9

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

z

slide-10
SLIDE 10

“When everyone is super, 
 no one is super”

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

z

slide-11
SLIDE 11

“When everyone is super, no one is super”

10

slide-12
SLIDE 12

11

slide-13
SLIDE 13

11

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

slide-14
SLIDE 14

12

Higher “data to ink” ratio

slide-15
SLIDE 15

13

Problems?

slide-16
SLIDE 16

14

slide-17
SLIDE 17

15

This reminds you of what?

Bar Charts

slide-18
SLIDE 18

16

Better than Christmas


(Use color brewer to find good color schemes)

slide-19
SLIDE 19

17

Company Profits

slide-20
SLIDE 20

17

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

Company Profits

slide-21
SLIDE 21

18

slide-22
SLIDE 22

19

slide-23
SLIDE 23

19

Misleading Bar Charts

slide-24
SLIDE 24

20

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

slide-25
SLIDE 25

21

Disorienting color bars

slide-26
SLIDE 26

22

Use gradation

slide-27
SLIDE 27

23

slide-28
SLIDE 28

23

Avoid Tilted or Rotated Labels

slide-29
SLIDE 29

24

Bars Can be Horizontal

http://www.apple.com/macbook-pro/performance-retina/

slide-30
SLIDE 30

24

Bars Can be Horizontal

When labels are hard to read, try horizontal

  • layout. (Don’t settle for the default.)

http://www.apple.com/macbook-pro/performance-retina/

slide-31
SLIDE 31

25

Line Charts

Can you improve the tick labels?

slide-32
SLIDE 32

26

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

slide-33
SLIDE 33

27

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

Fever Line

slide-34
SLIDE 34

28

Fever Line

slide-35
SLIDE 35

29

Multiple Patterned Lines 
 in one chart

We see this often in academic papers. Better ways?

slide-36
SLIDE 36

30

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

slide-37
SLIDE 37

31

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

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

slide-38
SLIDE 38

32

The Dreaded Pie Charts

Why people like to use pie charts?

slide-39
SLIDE 39

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

slide-40
SLIDE 40

34

slide-41
SLIDE 41

Log scale instead of linear scale

Include numbers from different orders of magnitude

35

slide-42
SLIDE 42

36

Example

log-log

slide-43
SLIDE 43

37

Example

“log” also works well for time

slide-44
SLIDE 44

38

OK for outliers that are *really* different

slide-45
SLIDE 45

Destroying your great results with poor powerpoint

Bad color schemes Bad fonts Too much animation Too much data

39

100 times faster!

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

Don McMillan: Life After Death by PowerPoint

can you read this?

slide-46
SLIDE 46

Destroying your great results with poor powerpoint

  • Color schemes: start with black & white, add colors if needed
  • Fonts: sans-serif generally looks nice
  • On Mac: Helvetica is great start
  • On Windows: Arial?
  • Too much animation: start with no animation, then add if

appropriate

  • Too much data: don’t just copy figures from paper and past

them on the slides!

40

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

Don McMillan: Life After Death by PowerPoint

slide-47
SLIDE 47

Suggestions: use pictures whenever appropriate

“Pictures” include most non-text elements: 
 tables, diagrams, charts, etc. Why?

  • “A picture is worth a thousand words”
  • People like pictures and love movies.
  • Picture is often more succinct, memorable

41

slide-48
SLIDE 48

Figures should be self-contained

Why?

  • Don’t make people go back and forth between text & figure
  • People skim; look at “interesting” things first
  • Especially in academia, busy reviewers look at figures first
  • Bad figures -> bad first impression 


(lower chance of paper acceptance) How to fix?

  • Succinctly describe your main messages 


(what you want the readers to learn)

42

slide-49
SLIDE 49

43

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

Example

slide-50
SLIDE 50

Crown-jewel figure on first page

(nice to have)

Why?

  • Give an overview of what readers is going to

get -- cut to the chase

  • Again, people like to see interesting things

How to do it?

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

44

slide-51
SLIDE 51

45

Example

slide-52
SLIDE 52

46

Example

slide-53
SLIDE 53

Suggestion: Use legible fonts

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

For printed materials, print them out and check! For slides, rule of thumb is about 7 lines of text per slide.

47

slide-54
SLIDE 54

Suggestion: you probably need to redo your figure for slides

Designing for print is different from designing for the screen

  • Resolution (which is higher?)
  • Levels of details (people mostly want a few

“take-away” messages from your talk)

48

slide-55
SLIDE 55

49

Example

slide-56
SLIDE 56

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