i247: Information Visualization and Presentation Marti Hearst

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i247 Information Visualization and
PresentationMarti Hearst
Design Choices in Building Basic Graphs    
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Few on How to Show Information
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Few on Showing Information
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Few on Showing Information
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Few on How to Show Information
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Few on How to Show Information
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Few on Showing Information
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Few on Showing Information
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Which Types of Graphs for Which Kinds of Data?
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Combining Data Types in Graphs
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Last time Class exercise

• What did people find?

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Example Titanic Data

• The data contains counts of women, men, children,
  the class of room they had, if they were
  passengers or crew, and if they survived or not.
• What kinds of questions to we want to ask of this
  data?

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Which Properties are Appropriate for Which
Information Types?
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Bertins Graphical Vocabulary

• Position
• Marks
• Points
• Lines
• Areas
• Retinal variables
• Color
• Size
• Shape

• Grayscale
• Orientation
• Texture

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Key Idea

• How should data of various types be encoded into
  visual features?
• Mapping quantities into shapes does not work!
• 10 100
• But using extent works well

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Interpretations of Graphical Vocabulary

• Some properties can be discriminated more
  accurately but dont have intrinsic meaning
• (Senay Ingatious 97, Kosslyn, others)
• Density (Greyscale)
• Darker -gt More
• Size / Length / Area
• Larger -gt More
• Position
• Leftmost -gt first,
• Topmost -gt first
• Hue
• no intrinsic meaning
• good for highlighting
• Slope / Shape
• no intrinsic meaning
• good for contrast

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Accuracy Ranking of Quantitative Perceptual
TasksEstimated only pairwise comparisons have
been validated.(Mackinlay 88 from Cleveland
McGill)
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Expressiveness rankings for Info Vis tasks
Bertin, adapted from Spence 2006
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Which properties used for what?

• Fews Table

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More to come

• Well also talk about Gestalt properties later,
  when we discuss perceptual principles in more
  detail.

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Next Time

• Well also talk about Gestalt properties later,
  when we discuss perceptual principles in more
  detail.