CMC/CC A Visual Communication

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CMC/CC AVisual Communication

• Master IK, CIW, MMI
• L.M. Bosveld-de Smet
• Mon. 27/11/06 16.00-18.00

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Outline

• Varieties of visualizations
• Visual communication in general
• Obvious advantages of pictures
• Important general concepts

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Carbon Cycle
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Elastic Collision
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Weather Map
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Alzheimers Disease Brains
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Visits Respiratory Disease
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Differences
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Good and Bad Pictures

• Bertin, 1967
• Combien de dessins admirablement exécutés et
  richement reproduits ne communiquent quune
  information dérisoire et inutile? Que de papier
  et de couleurs perdus. Tandis que des croquis
  malhabiles mais correctement construits
  deviennent les meilleurs instruments de la
  découverte et de la pédagogie
• Tufte, 1983
• Graphical excellence
• consists of complex ideas communicated with
  clarity, precision, and efficiency
• is that which gives the viewer the greatest
  number of ideas in the shortest time with the
  least ink in the smallest space
• requires telling the truth about the data

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Visual Communication simplified
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Natural vs. Unnatural Link
c
c
b
a
b
a
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Misleading Link
Gregory
Charles
Bill
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Visual Communication more complex
Data Tables
Visual Structures
Raw Data
Views
Data Transformations
Visual Mappings
View Transformations
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Monk Puzzle (Winn, 1987)

• A monk went to the temple at the top of a holy
  mountain to meditate and pray. He started out
  early one morning along the path that led up to
  the temple. Because he was an old man, and the
  way was steep and arduous, he frequently slowed
  his pace, and even sat and rested a while beside
  the path. Toward evening, he came to the temple
  at the top.
• After several days of meditation and prayer, it
  was time for him to leave. Early in the morning,
  he set off back down the path. Again, he
  frequently changed his pace and rested by the
  way. He arrived back at the bottom in the
  evening.
• Show that there is one single point on the path
  up the mountain where the monk will be at
  precisely the same time both when he goes up and
  when he comes down.

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Advantages Visualization
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Shimojima (2004)

• Inferential and Expressive Capacities of
  Graphical Representations Survey and Some
  Generalizations
• Crucial traits of varieties of visual
  representations
• Free ride properties
• Auto-consistency
• Over-specificity
• Meaning derivation properties

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A toy example
Suppose

• Piet, Jan, Wim, Anna, Mieke join in a running
  competition.
• They run the race for themselves and finish each
  in a different time (no ties).

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Comparison of different modalities

• We can use different representations for the
  information that Jans score is better than Piets

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• Formula first-order logic (FOL)
• 2-place predicate
• DEFEAT
• with 2 arguments
• jan and piet

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Position diagram (PD) Horizontal relation of
names indicates order of arrival of participants.
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English well-formed sentence meaning that Jan
defeated Piet, i.e. that Jan ran the race faster
than Piet did.
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PD more in detail

• Syntactic rules
• Two or more of the names Jan, Piet, Wim,
  Anna, and Mieke appear in a horizontal row.
• The same name appears at most once.

• Semantic rules
• If the name X appears to the left of the name Y,
  the bearer of X defeated the bearer of Y.

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1. Free Ride
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Difference 1

• Represent the following information
• Jan 16.34 Piet 20.80 Mieke 25.40

ENGL.
Jan defeated Piet and Mieke was beaten by Piet.
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The PD adds information for free that is not
available in FOL nor in English
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• In PD, expressing certain sets of information
  results in the expression of additional,
  consequential information.

Free rides

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Other exampleVenn diagrams

• Represent All As are Bs No Bs are Cs.

Expressing certain sets of information results in
the expression of additional, consequential
information No As are Cs
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Other exampleEuler circles

• Express
• A ? B
• C n B Ø

Free ride C n A Ø
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Another example maps

• Express
• Bs house is in front of Fs house on the other
  side of the river.

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Barwise Etchemendy (1990)
Diagrams are physical situations.As such, they
obey their own set of constraintsBy choosing a
representational scheme appropriately, so that
the constraints on the diagrams have a good match
with the constraints on the described situation,
the diagram can generate a lot of information
that the user never need infer. Rather, the user
can simply read off facts from the diagram as
needed.
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Assumption
A representation X expresses information about
the represented object Y by having a property
that indicates the corresponding property of Y.
Property a
Represented object Y
indicates
Representation X
Property a
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Example of PDs
Jan defeated Piet
A particular competition
indicates
A specific PD
name Jan appears to the left of name Piet
Jan Piet
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Example Euler circles
A ? B
A specific group of circles
indicates
A specific Euler diagram
circle A appears inside circle B
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Condition for Free Ride in PD system
Jan defeated Mieke.
The name Jan appears to the left of Mieke.
The name Mieke appears to the right of the name
Piet
The name Jan appears to the left of the name
Piet
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Free Ride Euler Diagram
C n B ø
C n A ø
A ? B
A circle C and circle B do not overlap.
A circle A appears inside another circle B.
Circle C and circle A do not overlap.
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Condition for Free Ride General
(Shimojima 1996a, 1996b)
constraint


constraint
Constraints on representations themselves track
constraints in the represented domain.
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Thus
A system with a free-ride property supports
deductive inference through physical manipulation
of representations on an external display, not in
the head.
A (paradigm) case of distributed cognition
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Recognition Problem
Free rides only guarantee the expression of
consequential information in the representation,
not its recognition by the user.

• Cheap rides (Gurr, Lee, and Stenning 1998, Gurr
  1999)
• Expertise in diagram construction to facilitate
  the recognition of useful consequences (Novak
  1995)

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2. Over-Specificity
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Difference 2

• Express
• Jan defeated Piet.
• Mieke defeated Piet.

PD
?
?
Jan Mieke Piet
Mieke Jan Piet
English
Jan defeated Piet and Mieke defeated Piet.
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• Druk uit
• Jan defeated Piet.
• Mieke defeated Piet.

PD system cant express the info without
additional infowhile FOL and English can!
PD
?
?
Jan Mieke Piet
Mieke Jan Piet
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• In PD, certain sets of information cannot be
  expressed without expressing additional,
  non-warranted information.

Over-specificity

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Another example Euler circles

• Express
• A ? B
• C n B ? ø

Where to draw circle C?
A
A
B
B
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Another example Maps

• Express
• Ks house is located between As house and Bs
  house.

Where to put this house?
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Lawson (1997)
, there are some ways in which a picture can
often carry too much information or indicate a
degree of precision which may be
inappropriate.It would be difficult to construct
a drawing which did not suggest other features of
the form of the finished product which might
restrict a future designer. (p. 242.)
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Analysis of over-specificity in PD
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Analysis of over-specificity General
(Shimojima 1996b)
constraint
constraint
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3. Derived Meaning
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Difference 3

• Express
• Jan defeated Piet.
• Anna defeated Jan.
• Piet defeated Mieke.
• Mieke defeated Wim

Jan defeated Piet, Piet defeated Mieke, Anna
defeated Jan and Mieke defeated Wim.
English
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Express Jan defeated Piet. Anna defeated
Jan. Piet defeated Mieke. Mieke defeated Wim
You can count the names to find out the number of
participants satisfying a certain condition
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• In PD, some additional meaning relation holds
  that does not hold in FOL and English.
• Moreover, that relation is derivative in that it
  is not written in basic semantic rules.

Derivative Meaning

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Another example Table
Anna Jan Piet Mieke Wim
Jan Mieke Wim Anna Piet
Jan O O O
Mieke O
Wim
Anna O O O O
Piet O O
Number of circles in a column means the number of
participants that are not defeated
Number of circles in a row means the number of
participants that are defeated
Extra meaning relation
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Analysis of derived meaning in PDs
(1) is valid
(1) at least 2 participants defeated Mieke

constraint
(1) at least 2 names are at the left of the name
Mieke

constraint
(1) is valid
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Another example Scatter plots
From Tufte (1983)

• The shape formed by dots means a general fact
  about the distribution
• Existence of correlation,
• Its strength,
• Existence of an exceptional instance, etc.

Additional meaning relation
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Kosslyn (1994)
Scatter plots...employ point symbols (such
as dots, small triangles, or squares) as content
elements. The height of each point symbol
indicates an amount. These displays typically
include so many points that they form a cloud
information is conveyed by the shape and the
density of the cloud. (p. 46.)
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Thus
A representation system with a meaning derivation
property allows the simultaneous presentation of
local information and global information implied
by the local information.
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Lowe (1989)
Indeed, the central purpose of many scientific
diagrams is to depict relationships and
interactions.If students are to understand such
diagrams, they need to be able to do more than
just decode the symbols used. They must also be
able to uncover and assimilate salient
relationships between the symbols that constitute
a diagram and appreciate how these relationships
map onto the real-world situation being
represented. (p. 28.)
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Influencing Factors

• Context (educational, professional, )
• Nature of task (recall, recognition, problem
  solving, )
• User s prior knowledge, skills, preferences,
  experiences,