What is Information Visualization?

• ``Transformation of the symbolic into the geometric''
  (McCormick et al., 1987)
• ``... augmenting this natural intelligence in the best possible way, ... finding the artificial memory that best supports our natural means of perception.''
  (Bertin, 1983)
• The depiction of information using spatial or graphical representations, to facilitate comparison, pattern recognition, change detection, and other cognitive skills that make use of the visual system.

Goals of Information Visualization:

Aid in:

• Analysis
• Explanation
• Decision Making
• Exploration
• Communication
• Reasoning about Information

More specifically, visualization should:

• Make large datasets coherent
  (Present huge amounts of information compactly)
• Present information from various viewpoints
• Present information at several levels of detail
  (from overviews to fine structure)
• Support visual comparisons
• Show the gaps
• Tell stories about the data

This is also true of other forms of information presentation

Why Visualization?

• Human perceptual abilities are underutilized
• Use the eye for pattern recognition
• People are good at
  • scanning
  • recognizing
  • recalling images
• Graphical elements facilitate comparisons via
  • length
  • shape
  • orientation
  • texture
• Animation shows changes across time
• Important to link with other communication forms
• "Verbal vs. Visual"

The Role of Computers

• Hand-drawn illustration throughout human history
• Statistical Data Graphics dates from William Playfair (1786)
• Computers facilitate:
  • Access to large datasets
  • Interaction
  • Animation
  • Range of scales
  • Precision
  • Elimination of tedious work
  • New methods of display
• Many of the new methods have not be evaluated

This Course

• Visualization of large, abstract datasets*
  • Examples:
    • heterogeneous databases
    • networked systems
    • text collections
  • Goal: show patterns, clusters, gaps, outliers
  • Successively reveal and refine the information
• Design of interactive information presentations
• Techniques:
  • Traditional approaches to statistical data graphics
  • Innovative computational approaches
  • Animation + interaction seem especially powerful
• Assessing usefulness

  *Illustrations of ``real-world'' phenomena are more straightforward.

What we are not covering

• Scientific visualizaton
• Statistics
• Cartography (maps)
• Education
• Games
• GUIs in general (take Landay's course or IS213)
• Computer graphics in general (take Sequin's or Barsky's course)
• Computational geometry (take Bern's course)

Case Study: Space Shuttle Disaster 1986

by Edward Tufte (Visual Explanations, 1990)
(See handout)

Main points:

• It wasn't a question of finding the right problem, people were debating what turned out to be the actual cause of the explosion.
• There may have been many different social factors at play.
• The facts remain:
  • The data was available, but
  • The data was not presented in a convincing way

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