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 Lecture 12:
Interaction

April 21, 2011

 COMP 150-7
 Visualization
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                      Interaction

• What is visualization without interaction?

• What is the role of interaction in visualization?

• Is it
  •   visualization + interaction?
  •   interaction + visualization?

• What is interaction?
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           Shneiderman’s Mantra

• Ben Shneiderman, “The Eyes Have It: A Task
  by Data Type Taxonomy for Information
  Visualization”, 1996 IEEE Computer Society
  Press

• “Overview first, zoom and filter, then details-
  on-demand”
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              Shneiderman’s Mantra

• Overview first, zoom and filter, then details-
  on-demand

  • Overview
     •   Visualize the data in its entirety
  • Zoom and filter
     •   Let the user select the important stuff
  • Details on demand
     •   Show what the user selected
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           Shneiderman’s Mantra

• Why is this important?



• There are very few “rules” in visualization,
  this Mantra is one of the more important
  ones.
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               Zoom and Filter

• What is the user really doing when they
  perform “zoom” or “filter”?

• Interaction ==
  • “direct manipulation and instantaneous change”
    (Becker et al. 1987)
  • “the communication between user and the
    system” (Dix et al. 1998)
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                “Little Brother”

• “Interaction is rarely the main focus of
  research efforts in the field, essentially
  making it the ‘little brother’ of [information
  visualization]” (Yi et al. InfoVis 2007)

• As shown by Shneiderman, visualization ==
  • Visual representation
  • Interaction
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                 “Little Brother”

• In most visualization courses,
  • Visual representation is the focus
  • Interaction receives little attention


• But interaction is just as important if not
  more so!
  • Lots of opportunities because few people are
    thinking about it
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                        Research

• Designing completely new visual representations
  is hard
  •   The domain is well covered

• But given the same visualization, different
  interactions can allow different explorations,
  analyses, and discoveries

• This is because interaction makes a visualization
  come “alive”
  •   otherwise visualization is just a drawing on a piece of
      paper
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                For Example…

• What’s wrong with a (static) stacked graph?
  • http://www.meandeviation.com/dancing-
    histograms/hist.html
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Questions?
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                    Technically…

• What makes a visualization interactive?
  •   In computer graphics, 12 frames per second is
      thought to be interactive because the animation will
      appear “smooth” to most people
  •   12 fps == 0.08 second per frame


• Cognitively,
  •   < 0.1 second : animation, continuity
  •   < 1 second: system response, conversation break
  •   < 10 second: cognitive response
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                  Examples

• http://www.weather-
  forecast.com/locations/Roma/map



• http://www.digitalhistory.uh.edu/timeline/ti
  melineN.cfm
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           Interaction as Selection

• In most interactive visualization systems, we
  think of the interaction as the ability to select
  or filter some data items
  • Shneiderman’s “zoom and filter”


• What does that mean technically?
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          Database Background

• SQL Query. Example:

    SELECT person
    FROM datasetTable
    WHERE (weight > 130) AND
           (weight < 180) AND
           (height > 5.8) AND
           (height < 6)
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         Database and Visualization

• This is the equivalent of a selection box in a
  scatter plot visualization


                                         Height = 6



                                         Height = 5.8
                    weight = 130   weight = 180
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         Database and Visualization

• For a specific type of interaction (e.g. select,
  filter, zoom, etc.), there is often a 1:1
  mapping between the interactions and
  database queries

• Homefinder Example
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          Database and Visualization
• There is a nice mapping between
  each visual element with an
  attribute in the database

  SELECT latitude, longitude
      FROM homesTable
      WHERE (distance > 5) AND
               (distance < 10) AND
               (price > 100,000) AND
               (price < 300,000) AND
               (bedrooms > 3) AND
               (garage = TRUE) AND
               (fireplace = FALSE)
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              Query Relaxation

• “Generalized Selection via Interactive Query
  Relaxation” (Heer et al. CHI 2008)

• http://vis.berkeley.edu/papers/generalized_s
  election/
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          Database Strength and Weakness
• Strengths:
  •   Generalizable
  •   Separates data from visualization cleanly
  •   SQL is a very stable language that is very complete for
      interacting with data stored in relational databases

• Weaknesses:
  •   Dynamic query construction is tricky
  •   DB overhead
  •   Speed is a problem
      •    Network speed
      •    DB searching speed
      •    Parsing DB returned tuples
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               Conjunctive Form

• A selection / filtering / zooming interaction ==
  database query

• It can also be thought of as a conjunctive
  form
     !(A1 V A2) ^ A3 V (A4 V A5 ^ A6) V …

     where A1 could be the clause (price > 200)
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                  Conjunctive Form

• Very similar to SQL query, but can be built in software

• Has some of the similar limitations as SQL in that the
  clauses need to be pre-built
  •   Such that a data attribute needs to be “hard-coded” to a
      visual element

• Consider a slider that connects to two or more
  attributes
  (http://gravis.cs.unibas.ch/publications/2007/VIS07_S
  mith.pdf)
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Questions?
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            Interaction Taxonomy

• Not all interactions are data-driven,
  sometimes they are just used to modify the
  visual representation…

• A taxonomy of interaction types based on a
  large survey of papers and systems (Yi et al.
  2007)

• The taxonomy emphasizes “user intent” as
  the categorization
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            7 Types of Interactions

•   Select
•   Explore
•   Reconfigure
•   Encode
•   Abstract/Elaborate
•   Filter
•   Connect
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                   1. Select

• “Mark something
  as interesting”
  • Hovering, popups,
    etc


• Can be data-driven
  (i.e. using SQL or
  conjunctives)
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                    2. Explore

• “Show me something
  different”
  • Hyperlink, social
    network


• Can be data-driven, but
  is a bit more
  complicated now…

                                 http://www.visualthesaurus.com
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                 3. Reconfigure

• “Show me a different arrangement”
  • Sorting, moving dimensions in Parallel
    Coordinates


• Not data related –
   purely visual
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            3. Reconfigure


Rearrange




Sort
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                    4. Encode

• “Show me a different representation”
  • Switching from bar-chart to line graph
    (assignment 2), changing font, changing
    orientation, etc.

• Not data related

• Important for thinking about the same data
  with different visualizations
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4. Encode
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           5. Abstract / Elaborate

• “Show me more or less detail”
  • Google map zooming, details on demand, popup
    lens


• Possibly a combination
  of data and
  visualization
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                     6. Filter

• “Show me something conditionally”
  • Dynamic query (Homefinder), Attribute Explorer,
    Google auto-complete


• Could be data-driven
  or visualization driven
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                       6. Filter

• Magic Lenses (Bier et al. 1993)
    •   http://www.open-video.org/details.php?videoid=8167
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                   7. Connect

• “Show me related items”
  • Brushing-and-linking (coordinated visualizations)

• Does not need to be data-driven
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                    7. Connect




Matkovic, IV 2008
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Questions?
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         Supporting Representation?

• Interaction is vital to information visualization

• Without interaction, visualization is static.
  With interaction, visualization can assist
  analytical thinking

• In this context, visualization + interaction,
  interaction is the “little brother”
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           Supporting Interaction?

• Information visualization is vital to interaction

• Without representation, there is nothing to
  interact with. With representation,
  interaction can assist analytical thinking

• In this context, interaction + visualization,
  representation is the “little brother”
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                     Huh?


• Does this work at all?



• What’s wrong with this reasoning?

				
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