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Information visualization lecture 2

perception and principles
Katrien Verbert
Department of Computer Science
Faculty of S...
perception
how our brain perceives and interprets visuals

27/02/14

pag. 2
Moving Illusions

h"p://www.youtube.com/watch?v=Iw8idyw_N6Q	
  
Watch	
  00:00	
  –	
  07:23	
  
	
  
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pag. 5
pre-attentive processing
How do we make things pop-out?

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pag. 6
Where is Waldo?

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pag. 7
How many 3’s?

1281768756138976546984506985604982826762
9809858458224509856458945098450980943585
9091030209905959595772564...
How many 3’s?

1281768756138976546984506985604982826762
9809858458224509856458945098450980943585
9091030209905959595772564...
Pre-attentive vs. attentive
Differences in speed of perception
Pre-attentive

≤500 ms
≤10 ms
parallel processing

Slide	
 ...
Pre-attentive processing

“An understanding of what is processed pre-attentively is
probably the most important contributi...
Different shapes can often pop out

Shape
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pag. 12
A single lack of enclosure can quickly be
identified pre-attentively

Enclosure
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Pre-attentive processing:
‘things that pop out’

Orientation

The	
  ‘odd	
  one	
  out’	
  can	
  quickly	
  be	
  
idenJ...
A different colour can be
pre-attentively identified

Colour
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Did you notice the red square?

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With conjunction encoding the red square
is not pre-attentively identified

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But multiple pop-outs are possible
Usage
load

Forced
termination
rate

Number
of users

Direction
of growth

Predominant
...
Multiple pop-outs

RepresentaJon	
  of	
  a"ributes	
  
associated	
  with	
  a	
  network	
  of	
  
mobile	
  telephone	
...
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pag. 20
Pre-attentive features

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Where is Waldo?

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 22
Where is Waldo?

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 23
encoding methods

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Magnitude estimation
How much bigger is the lower bar?

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

27/02/1...
Magnitude estimation
How much bigger is the lower bar?

X	
  4	
  

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	...
Magnitude estimation
How much bigger is the right circle?

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

27/0...
Magnitude estimation
How much bigger is the right circle?

X	
  5	
  

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
...
Magnitude estimation
How much bigger is the right circle?

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

27/0...
Magnitude estimation
How much bigger is the right circle?

X	
  9	
  

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
...
Apparent magnitude curves

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

h"p://makingmaps.net/2007/08/28/
per...
Which one is more accurate?

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 32
Perceptual or apparent scaling
Compensating magnitude to match perception

Slide	
  adapted	
  from	
  Michael	
  Porath	
...
Accuracy of judgement of encoded
quantitative data
Position

Most accurate

Length

Angle
Slope
Area
Volume
Colour
Density...
Association
The marks can
be perceived as
SIMILAR

Size

Value

Texture

Colour

Orientation

Shape

Selection

Order

The...
Example application that uses
different encoding methods

User query
Osteoporosis
Prevention
Research
First	
  the	
  user...
TileBar: which encoding methods
are used for which purposes?
‘Recent	
  advances	
  in	
  the	
  world	
  of	
  drugs’	
  ...
Quantitative, ordinal and
categorical data

Quantitative
Position
Length
Angle
Slope
Area
Volume
Density
Shape
Treble

Ord...
Gestalt grouping

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pag. 39
h"p://www.youtube.com/watch?v=ZWucNQawpWY	
  

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pag. 40
Principles:
figure and ground

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 41
Principles:
proximity

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 42
Principles:
proximity

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 43
Principles:
similarity

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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Principles:
connectedness

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 45
Principles:
continuity

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 46
Principles:
continuity

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 47
Principles:
continuity

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 48
Principles:
closure

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 49
Principles:
closure

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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Principles:
closure

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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Principles:
closure

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 52
Principles:
smallness

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 53
Principles:
smallness

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 54
Principles:
surroundedness

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 55
Principles:
surroundness

Slide	
  adapted	
  from	
  Michael	
  Porath	
  	
  	
  

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pag. 56
Guideline
Use a combination of closure, common region and layout to
ensure that data entities are represented by graphical...
Application

h"p://www.youtube.com/watch?v=LlzuJqZ797U	
  (watch	
  3:39-­‐5:09)	
  
	
  
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pag. 58
Color

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pag. 59
Find the cherries

“Color	
  helps	
  us	
  break	
  camouflage”	
  
[Ware,	
  2013]	
  
Slide	
  adapted	
  from	
  S.	
  ...
Snow white may be color blind?

Slide	
  adapted	
  from	
  S.	
  Hsiao	
  

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pag. 61
Ready to eat

Slide	
  adapted	
  from	
  S.	
  Hsiao	
  

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How we see color

h"p://www.youtube.com/watch?v=l8_fZPHasdo	
  
	
  
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pag. 63
Our eyes

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Trichromacy Theory: 3 color cones
sensitivity functions

Slide	
  adapted	
  from	
  S.	
  Hsiao	
  

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pag. 65
10%CAUCASIAN MALE IS
COLOR BLIND!

Slide	
  adapted	
  from	
  S.	
  Hsiao	
  

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Color Tests

•  The individual with normal color vision will see a 5 revealed in
the dot pattern.
•  An individual with Re...
Color blindness

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We often take color for granted
•  How do blind people learn colours?
•  How do colourblind people drive?

Slide	
  adapte...
Color blindness: consequences

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Colors have meaning!

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How to use colors

•  hue: categorical

•  saturation: ordinal and quantitative

•  luminance: ordinal and quantitative

2...
Sequential color schemes

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Diverging color schemes

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Qualitative color schemes

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ColorBrewer2.org

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Adobe Kuler: Focus on aesthetics

Good	
  Color	
  Scales	
  
	
  
h"p://kuler.adobe.com	
  
pag. 78
27/02/14
	
  
Good or bad use of colors?

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h"p://eagereyes.org/basics/rainbow-­‐color-­‐map	
  
	
  

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Interaction of color

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Interaction of color

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Relative differences

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Interaction of color

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Simultaneous contrast

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Simultaneous contrast

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Simultaneous contrast

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Simultaneous contrast

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pag. 88
Simultaneous brightness contrast

[Ware,	
  1988]	
  
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pag. 89
The Chevreul illusion

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Simultaneous contrast and errors in
reading maps

Gravity	
  map	
  of	
  the	
  North	
  AtlanJc	
  Ocean.	
  Large	
  er...
Guideline

Avoid using gray scales as a method for representing more than
a few (two to four) numerical values [Ware, 2013...
All colors are equal
…but they are not perceived as the same

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pag. 93
All colors are equal
…but they are not perceived as the same

Luminance Value

Perceived lightness

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pag. 94
Luminance values

Src:	
  h>p://www.workwithcolor.com/color-­‐luminance-­‐2233.htm	
  

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pag. 95
Color decisions need to consider
luminance / contrast

Slide	
  adapted	
  from	
  S.	
  Hsiao	
  

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pag. 96
Test a composition for contrast
h"p://www.workwithcolor.com/to-­‐black-­‐and-­‐white-­‐picture-­‐converter-­‐01.htm	
  
	
...
HSL color picker

h"p://www.workwithcolor.com/hsl-­‐color-­‐picker-­‐01.htm	
  
	
  
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pag. 98
Haloing effect
•  Enhancing the edges
•  Luminance contrast as a
highlighting method

[Ware,	
  2013]	
  
Slide	
  adapted...
Saturation

Slide	
  adapted	
  from	
  S.	
  Hsiao	
  

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pag. 100
Highlighting: make small subset clearly
distinct from the rest

same principles apply to the highlighting of text or other...
Guidelines

•  Use more saturated colors for small symbols, thin lines, or
small areas.
•  Use less saturated colors for l...
Cross-cultural naming

More than 100 languages showed that primary color terms are
consistent across cultures (Berlin & Ka...
Ware’s Recommended Colors for Labeling

Red, Green, Yellow, Blue, Black, White, Pink, Cyan, Gray, Orange, Brown, Purple.
T...
Guideline

Use easy-to-remember and consistent color codes in color pallets
Red, green, blue and yellow are hard-wired int...
Chromostereopsis

Slide	
  adapted	
  from	
  S.	
  Hsiao	
  

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pag. 106
How we used to think it works

Old	
  model:	
  Light	
  of	
  different	
  wavelengths	
  is	
  focused	
  differently	
  b...
What we know

	
  

Current	
  model:	
  Light	
  of	
  different	
  wavelengths	
  is	
  refracted	
  differently	
  by	
  ...
chromostereopsis
If we use in the same image two far pure colors the eye is not
able to focus both of them

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pag....
Easy to read?

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Easy to read?

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How to use chromostereopsis

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How to use chromostereopsis

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Good or bad?

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pag. 114
Good or bad?

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Solution: use colors that are less saturated

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Guidelines
•  Beware of interactions between some colors (e.g. red/blue)
•  Use can be good: for highlighting, creating 3D...
We are drawn by colors!

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Do different colors affect mood?
h"p://www.factmonster.com/spot/colors1.html	
  
	
  

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pag. 119
Moodjam.com

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some examples

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Good or bad us of colors?

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Good or bad use of colors?

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pag. 123
Good or bad?

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pag. 124
Good or bad?

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pag. 125
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Good or bad use of colors?

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Some take away messages
• 
• 
• 
• 
• 
• 

• 
• 

Color is excellent for labeling and categorization.
(However, only small...
Readings

Required
•  Harrower, M., & Brewer, C. A. (2003). ColorBrewer. org: an online
tool for selecting colour schemes ...
Optical Illusions

•  Joy of Visual Perception by Pete Kaiser

132
Information Visualization Course, Katy Börner, Indiana ...
Questions?

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References
•  Pourang Irani and Rasit Eskicioglu. (2003). A Space-filling
Visualization Technique for Cellular Network Dat...
evaluation experiment

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pag. 135
learning dashboards:
visualizing emotion, time spent
and distractions

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pag. 136
Learning analytics dashboards

Govaerts,	
  S.,	
  Verbert,	
  K.,	
  Duval,	
  E.,	
  Abelardo,	
  P.	
  (2012).	
  The	
...
h"p://bit.ly/I7hve	
  

Santos JL, Verbert K, Govaerts S, Duval E (2013) Addressing learner issues with StepUp!: an Evalua...
GLASS: visualization of emotions

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Data collection
•  https://docs.google.com/forms/d/
1gHwVWHZLzWdSz1F37jA1Gungrl56bT215M6FYW3YqGY/
viewform
Or
•  bit.ly/N6...
Dashboard
•  Dashboard that visualizes your data and enables comparison
with data from other students will be made availab...
participation much appreciated!

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pag. 142
Information visualization: perception and principles
Information visualization: perception and principles
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Transcript of "Information visualization: perception and principles"

  1. 1. Information visualization lecture 2 perception and principles Katrien Verbert Department of Computer Science Faculty of Science Vrije Universiteit Brussel katrien.verbert@vub.ac.be 27/02/14 pag. 1
  2. 2. perception how our brain perceives and interprets visuals 27/02/14 pag. 2
  3. 3. Moving Illusions h"p://www.youtube.com/watch?v=Iw8idyw_N6Q   Watch  00:00  –  07:23     27/02/14 pag. 5
  4. 4. pre-attentive processing How do we make things pop-out? 27/02/14 pag. 6
  5. 5. Where is Waldo? 27/02/14 pag. 7
  6. 6. How many 3’s? 1281768756138976546984506985604982826762 9809858458224509856458945098450980943585 9091030209905959595772564675050678904567 8845789809821677654876364908560912949686 27/02/14 pag. 8
  7. 7. How many 3’s? 1281768756138976546984506985604982826762 9809858458224509856458945098450980943585 9091030209905959595772564675050678904567 8845789809821677654876364908560912949686 27/02/14 pag. 9
  8. 8. Pre-attentive vs. attentive Differences in speed of perception Pre-attentive ≤500 ms ≤10 ms parallel processing Slide  adapted  from  Michael  Porath       Attentive task individual object >500 ms >10 ms sequential processing 27/02/14 pag. 10
  9. 9. Pre-attentive processing “An understanding of what is processed pre-attentively is probably the most important contribution that visual science can make to data visualization” (Ware, 2004, p. 19) 27/02/14 pag. 11
  10. 10. Different shapes can often pop out Shape 27/02/14 pag. 12
  11. 11. A single lack of enclosure can quickly be identified pre-attentively Enclosure 27/02/14 pag. 13
  12. 12. Pre-attentive processing: ‘things that pop out’ Orientation The  ‘odd  one  out’  can  quickly  be   idenJfied,  by  pre-­‐a"enJve  processing     27/02/14 pag. 14
  13. 13. A different colour can be pre-attentively identified Colour 27/02/14 pag. 15
  14. 14. Did you notice the red square? 27/02/14 pag. 16
  15. 15. With conjunction encoding the red square is not pre-attentively identified 27/02/14 pag. 17
  16. 16. But multiple pop-outs are possible Usage load Forced termination rate Number of users Direction of growth Predominant frequency New call blockage rate Call signal strength RepresentaJon  of  a"ributes  associated  with  a  mobile  telephone  network  cell  [Irani  and   pag. 18 27/02/14 Eskicioglu,  2003]  
  17. 17. Multiple pop-outs RepresentaJon  of  a"ributes   associated  with  a  network  of   mobile  telephone  cells,   averaged  over  one  hour   27/02/14 pag. 19
  18. 18. 27/02/14 pag. 20
  19. 19. Pre-attentive features 27/02/14 pag. 21
  20. 20. Where is Waldo? Slide  adapted  from  Michael  Porath       27/02/14 pag. 22
  21. 21. Where is Waldo? Slide  adapted  from  Michael  Porath       27/02/14 pag. 23
  22. 22. encoding methods 27/02/14 pag. 24
  23. 23. Magnitude estimation How much bigger is the lower bar? Slide  adapted  from  Michael  Porath       27/02/14 pag. 25
  24. 24. Magnitude estimation How much bigger is the lower bar? X  4   Slide  adapted  from  Michael  Porath       27/02/14 pag. 26
  25. 25. Magnitude estimation How much bigger is the right circle? Slide  adapted  from  Michael  Porath       27/02/14 pag. 27
  26. 26. Magnitude estimation How much bigger is the right circle? X  5   Slide  adapted  from  Michael  Porath       27/02/14 pag. 28
  27. 27. Magnitude estimation How much bigger is the right circle? Slide  adapted  from  Michael  Porath       27/02/14 pag. 29
  28. 28. Magnitude estimation How much bigger is the right circle? X  9   Slide  adapted  from  Michael  Porath       27/02/14 pag. 30
  29. 29. Apparent magnitude curves Slide  adapted  from  Michael  Porath       h"p://makingmaps.net/2007/08/28/ perceptual-­‐scaling-­‐of-­‐map-­‐symbols/   27/02/14   pag. 31
  30. 30. Which one is more accurate? Slide  adapted  from  Michael  Porath       27/02/14 pag. 32
  31. 31. Perceptual or apparent scaling Compensating magnitude to match perception Slide  adapted  from  Michael  Porath       27/02/14 pag. 33
  32. 32. Accuracy of judgement of encoded quantitative data Position Most accurate Length Angle Slope Area Volume Colour Density Least accurate Cleveland  and  McGill  (1984)     27/02/14 pag. 34
  33. 33. Association The marks can be perceived as SIMILAR Size Value Texture Colour Orientation Shape Selection Order The marks are perceived as DIFFERENT, forming families The marks are perceived as ORDERED Quantity The marks are perceived as PROPORTIONAL to each other Choice  of  encoding     •  Bertin’s guidance •  suitability of various encoding methods •  to support common tasks  
  34. 34. Example application that uses different encoding methods User query Osteoporosis Prevention Research First  the  user  specifies  three  topics  of  interest   27/02/14 pag. 36
  35. 35. TileBar: which encoding methods are used for which purposes? ‘Recent  advances  in  the  world  of  drugs’       Fortunately, scientific knowledge about this desease has grown, and there is reason for hope. Research is revealing that prevention may be achieved through estrogen replacement therapy for older women and through adequate calcium intake and regular weight-bearing exercise     for people of all ages. New approaches to diagnosis and treatment are also under active investigation. For this work to continue and for use to take advantage of the knowledge we have already gained, public awareness of osteoporosis and of the importance of further scientific research is essential.       (top)  The  TileBar  representaJon  of  the  relevance  of  paragraphs  to  the  topic  words:   pag. 37 27/02/14 (bo"om)  a  selected  paragraph  with  topic  words  highlighted  
  36. 36. Quantitative, ordinal and categorical data Quantitative Position Length Angle Slope Area Volume Density Shape Treble Ordinal Categorical Position Density Colour saturation Colour hue Texture Connection Containment Length Angle Slope Area Volume Position Colour hue Texture Connection Containment Density Colour saturation Shape Length Angle Slope Area Volume Bass Guidance  for  the  encoding  of  quanJtaJve,  ordinal  and  categorical  data  (Mackinlay  1986)   pag. 38 27/02/14  
  37. 37. Gestalt grouping 27/02/14 pag. 39
  38. 38. h"p://www.youtube.com/watch?v=ZWucNQawpWY   27/02/14 pag. 40
  39. 39. Principles: figure and ground Slide  adapted  from  Michael  Porath       27/02/14 pag. 41
  40. 40. Principles: proximity Slide  adapted  from  Michael  Porath       27/02/14 pag. 42
  41. 41. Principles: proximity Slide  adapted  from  Michael  Porath       27/02/14 pag. 43
  42. 42. Principles: similarity Slide  adapted  from  Michael  Porath       27/02/14 pag. 44
  43. 43. Principles: connectedness Slide  adapted  from  Michael  Porath       27/02/14 pag. 45
  44. 44. Principles: continuity Slide  adapted  from  Michael  Porath       27/02/14 pag. 46
  45. 45. Principles: continuity Slide  adapted  from  Michael  Porath       27/02/14 pag. 47
  46. 46. Principles: continuity Slide  adapted  from  Michael  Porath       27/02/14 pag. 48
  47. 47. Principles: closure Slide  adapted  from  Michael  Porath       27/02/14 pag. 49
  48. 48. Principles: closure Slide  adapted  from  Michael  Porath       27/02/14 pag. 50
  49. 49. Principles: closure Slide  adapted  from  Michael  Porath       27/02/14 pag. 51
  50. 50. Principles: closure Slide  adapted  from  Michael  Porath       27/02/14 pag. 52
  51. 51. Principles: smallness Slide  adapted  from  Michael  Porath       27/02/14 pag. 53
  52. 52. Principles: smallness Slide  adapted  from  Michael  Porath       27/02/14 pag. 54
  53. 53. Principles: surroundedness Slide  adapted  from  Michael  Porath       27/02/14 pag. 55
  54. 54. Principles: surroundness Slide  adapted  from  Michael  Porath       27/02/14 pag. 56
  55. 55. Guideline Use a combination of closure, common region and layout to ensure that data entities are represented by graphical patterns that will be perceived as figure, not ground. 27/02/14 pag. 57
  56. 56. Application h"p://www.youtube.com/watch?v=LlzuJqZ797U  (watch  3:39-­‐5:09)     27/02/14 pag. 58
  57. 57. Color 27/02/14 pag. 59
  58. 58. Find the cherries “Color  helps  us  break  camouflage”   [Ware,  2013]   Slide  adapted  from  S.  Hsiao   27/02/14 pag. 60
  59. 59. Snow white may be color blind? Slide  adapted  from  S.  Hsiao   27/02/14 pag. 61
  60. 60. Ready to eat Slide  adapted  from  S.  Hsiao   27/02/14 pag. 62
  61. 61. How we see color h"p://www.youtube.com/watch?v=l8_fZPHasdo     27/02/14 pag. 63
  62. 62. Our eyes 27/02/14 pag. 64
  63. 63. Trichromacy Theory: 3 color cones sensitivity functions Slide  adapted  from  S.  Hsiao   27/02/14 pag. 65
  64. 64. 10%CAUCASIAN MALE IS COLOR BLIND! Slide  adapted  from  S.  Hsiao   27/02/14 pag. 66
  65. 65. Color Tests •  The individual with normal color vision will see a 5 revealed in the dot pattern. •  An individual with Red/Green (the most common) color blindness will see a 2 revealed in the dots. http://www.visibone.com/colorblind/ Information Visualization Course, Katy Börner, Indiana University 27/02/14 pag. 67
  66. 66. Color blindness 27/02/14 pag. 68
  67. 67. We often take color for granted •  How do blind people learn colours? •  How do colourblind people drive? Slide  adapted  from  S.  Hsiao   27/02/14 pag. 69
  68. 68. Color blindness: consequences 27/02/14 pag. 70
  69. 69. Colors have meaning! 27/02/14 pag. 71
  70. 70. 27/02/14 pag. 72
  71. 71. How to use colors •  hue: categorical •  saturation: ordinal and quantitative •  luminance: ordinal and quantitative 27/02/14 pag. 73
  72. 72. Sequential color schemes 27/02/14 pag. 74
  73. 73. Diverging color schemes 27/02/14 pag. 75
  74. 74. Qualitative color schemes 27/02/14 pag. 76
  75. 75. ColorBrewer2.org 27/02/14 pag. 77
  76. 76. Adobe Kuler: Focus on aesthetics Good  Color  Scales     h"p://kuler.adobe.com   pag. 78 27/02/14  
  77. 77. Good or bad use of colors? 27/02/14 pag. 79
  78. 78. h"p://eagereyes.org/basics/rainbow-­‐color-­‐map     27/02/14 pag. 80
  79. 79. Interaction of color 27/02/14 pag. 81
  80. 80. Interaction of color 27/02/14 pag. 82
  81. 81. Relative differences 27/02/14 pag. 83
  82. 82. Interaction of color 27/02/14 pag. 84
  83. 83. Simultaneous contrast 27/02/14 pag. 85
  84. 84. Simultaneous contrast 27/02/14 pag. 86
  85. 85. Simultaneous contrast 27/02/14 pag. 87
  86. 86. Simultaneous contrast 27/02/14 pag. 88
  87. 87. Simultaneous brightness contrast [Ware,  1988]   27/02/14 pag. 89
  88. 88. The Chevreul illusion 27/02/14 pag. 90
  89. 89. Simultaneous contrast and errors in reading maps Gravity  map  of  the  North  AtlanJc  Ocean.  Large  errors  occur  when  gray-­‐scale  maps  are  read   using  a  key                20%  error  of  the  enJre  scale  [Ware,  1988]     27/02/14 pag. 91
  90. 90. Guideline Avoid using gray scales as a method for representing more than a few (two to four) numerical values [Ware, 2013] 27/02/14 pag. 92
  91. 91. All colors are equal …but they are not perceived as the same 27/02/14 pag. 93
  92. 92. All colors are equal …but they are not perceived as the same Luminance Value Perceived lightness 27/02/14 pag. 94
  93. 93. Luminance values Src:  h>p://www.workwithcolor.com/color-­‐luminance-­‐2233.htm   27/02/14 pag. 95
  94. 94. Color decisions need to consider luminance / contrast Slide  adapted  from  S.  Hsiao   27/02/14 pag. 96
  95. 95. Test a composition for contrast h"p://www.workwithcolor.com/to-­‐black-­‐and-­‐white-­‐picture-­‐converter-­‐01.htm     27/02/14 pag. 97
  96. 96. HSL color picker h"p://www.workwithcolor.com/hsl-­‐color-­‐picker-­‐01.htm     27/02/14 pag. 98
  97. 97. Haloing effect •  Enhancing the edges •  Luminance contrast as a highlighting method [Ware,  2013]   Slide  adapted  from  S.  Hsiao   27/02/14 pag. 99
  98. 98. Saturation Slide  adapted  from  S.  Hsiao   27/02/14 pag. 100
  99. 99. Highlighting: make small subset clearly distinct from the rest same principles apply to the highlighting of text or other features Slide  adapted  from  S.  Hsiao   27/02/14 pag. 101
  100. 100. Guidelines •  Use more saturated colors for small symbols, thin lines, or small areas. •  Use less saturated colors for large areas. 27/02/14 pag. 102
  101. 101. Cross-cultural naming More than 100 languages showed that primary color terms are consistent across cultures (Berlin & Kay, 1969) Slide  adapted  from  S.  Hsiao   27/02/14 pag. 103
  102. 102. Ware’s Recommended Colors for Labeling Red, Green, Yellow, Blue, Black, White, Pink, Cyan, Gray, Orange, Brown, Purple. The entire set corresponds to the eleven color names found to be the most common in a cross-cultural study, plus cyan (Berlin and Kay) Slide  adapted  from  Terrance  Brooke   27/02/14 pag. 104
  103. 103. Guideline Use easy-to-remember and consistent color codes in color pallets Red, green, blue and yellow are hard-wired into the brain as primaries. If it is necessary to remember a color coding, these colors are the first that should be considered. 27/02/14 pag. 105
  104. 104. Chromostereopsis Slide  adapted  from  S.  Hsiao   27/02/14 pag. 106
  105. 105. How we used to think it works Old  model:  Light  of  different  wavelengths  is  focused  differently  by  the  eye.   Src:  h>p://luminanze.com/wriMngs/chromostereopsis_in_ux_design.html   27/02/14 pag. 107
  106. 106. What we know   Current  model:  Light  of  different  wavelengths  is  refracted  differently  by  the  eye.   Src:  h>p://luminanze.com/wriMngs/chromostereopsis_in_ux_design.html   27/02/14 pag. 108
  107. 107. chromostereopsis If we use in the same image two far pure colors the eye is not able to focus both of them 27/02/14 pag. 109
  108. 108. Easy to read? 27/02/14 pag. 110
  109. 109. Easy to read? 27/02/14 pag. 111
  110. 110. How to use chromostereopsis 27/02/14 pag. 112
  111. 111. How to use chromostereopsis 27/02/14 pag. 113
  112. 112. Good or bad? 27/02/14 pag. 114
  113. 113. Good or bad? 27/02/14 pag. 115
  114. 114. Solution: use colors that are less saturated 27/02/14 pag. 116
  115. 115. Guidelines •  Beware of interactions between some colors (e.g. red/blue) •  Use can be good: for highlighting, creating 3D effect, etc. •  Resolve if unintended by: –  using  colors  that  are  less  saturated     –  surrounding  the  contrasMng  colors  with  a  background  that  moderates  the   effect  of  their  different  wavelengths   –  separa.ng  the  contrasMng  colors.     h>p://desdag.blogspot.be/2012/05/chromostereopsis-­‐design-­‐fails-­‐due-­‐to.html   27/02/14 pag. 117
  116. 116. We are drawn by colors! 27/02/14 pag. 118
  117. 117. Do different colors affect mood? h"p://www.factmonster.com/spot/colors1.html     27/02/14 pag. 119
  118. 118. Moodjam.com 27/02/14 pag. 120
  119. 119. some examples 27/02/14 pag. 121
  120. 120. Good or bad us of colors? 27/02/14 pag. 122
  121. 121. Good or bad use of colors? 27/02/14 pag. 123
  122. 122. Good or bad? 27/02/14 pag. 124
  123. 123. Good or bad? 27/02/14 pag. 125
  124. 124. 27/02/14 pag. 126
  125. 125. Good or bad use of colors? 27/02/14 pag. 127
  126. 126. 27/02/14 pag. 128
  127. 127. 27/02/14 pag. 129
  128. 128. Some take away messages •  •  •  •  •  •  •  •  Color is excellent for labeling and categorization. (However, only small number of colors can be used effectively) To show detail in visualization, always have considerable luminance contrast between background and foreground. Simultaneous contrast with background colors can dramatically alter color appearance, making color look like another. Beware of interaction between colors (e.g. red/blue). Small color coded objects should be given high saturation. Red, green, blue and yellow are hard-wired into the brain as primaries. If it is necessary to remember a color coding, these colors are the first that should be considered. Remember that colors have meanings: use appropriate color palettes for qualitative, quantitative and ordinal data. Respect the color blind. 27/02/14 pag. 130
  129. 129. Readings Required •  Harrower, M., & Brewer, C. A. (2003). ColorBrewer. org: an online tool for selecting colour schemes for maps. Cartographic Journal, The, 40(1), 27-37. Available at: http://www.albany.edu/faculty/fboscoe/papers/harrower2003.pdf Optional •  Ware, C. (2013). Information visualization: Perception for design. Chapter 3: Lightness, Brightness, Contrast, and Constancy. Available at: http://www.diliaranasirova.com/assets/PSYC579/pdfs/01.1Ware.pdf   27/02/14 pag. 131
  130. 130. Optical Illusions •  Joy of Visual Perception by Pete Kaiser 132 Information Visualization Course, Katy Börner, Indiana University 27/02/14 pag. 132
  131. 131. Questions? 27/02/14 pag. 133
  132. 132. References •  Pourang Irani and Rasit Eskicioglu. (2003). A Space-filling Visualization Technique for Cellular Network Data. In International Conference on Knowledge Management (IKNOW-03), 115-120 http://hci.cs.umanitoba.ca/assets/publication_files/2003Irani-IKNOW-CellularViz.pdf •  Ware, C. (2013). Information visualization: Perception for design. Chapter 3-5 •  Mackinlay, J. (1986). Automating the design of graphical presentations of relational information. ACM Transactions on Graphics (TOG), 5(2), 110-141. 27/02/14 pag. 134
  133. 133. evaluation experiment 27/02/14 pag. 135
  134. 134. learning dashboards: visualizing emotion, time spent and distractions 27/02/14 pag. 136
  135. 135. Learning analytics dashboards Govaerts,  S.,  Verbert,  K.,  Duval,  E.,  Abelardo,  P.  (2012).  The  student  acJvity  meter  for  awareness  and   self-­‐reflecJon.  In  :  CHI  EA  '12   27/02/14 pag. 137
  136. 136. h"p://bit.ly/I7hve   Santos JL, Verbert K, Govaerts S, Duval E (2013) Addressing learner issues with StepUp!: an Evaluation. In 138 27/02/14 pag. 138 Proceedings of LAK 13
  137. 137. GLASS: visualization of emotions 27/02/14 pag. 139
  138. 138. Data collection •  https://docs.google.com/forms/d/ 1gHwVWHZLzWdSz1F37jA1Gungrl56bT215M6FYW3YqGY/ viewform Or •  bit.ly/N6JTyD Anonymous! Choose your own ID. •  Report data once a week: preferably on Thursdays. 27/02/14 pag. 140
  139. 139. Dashboard •  Dashboard that visualizes your data and enables comparison with data from other students will be made available. •  Login with the same ID as the one you use for data collection. •  Will be made available one of the following weeks. 27/02/14 pag. 141
  140. 140. participation much appreciated! 27/02/14 pag. 142
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