Rules of Thumb
Information Visualization

What We Are Going to Learn

  • No unjustified 3D or 2D
  • Readable text
  • Eyes beat memory
  • Visualization mantra
  • Responsiveness is required
  • Function first, form next

No Unjustified 3D

Unjustified 3D Everywhere

Power of the Plane

Power of the Plane (cont.)

Magnitude channels

Danger of Depth

We don’t really live in 3D. 👉 We see in 2.05D.
  • Acquire more info on image plane quickly from eye movements
  • Acquire more info for depth more slowly, from head/body motion
Danger of Depth
Embedding Projector
https://projector.tensorflow.org/

Occlusion Hides Information

  • Interaction can resolve occlusion...
  • ... but at cost of time and cognitive load
Danger of Depth
Distortion Viewing Techniques for 3D Data. Carpendale et al. InfoVis1996.

Perspective?

Perspective distortion loses information.
  • Interferes with all size channel encodings
  • Power of the plane is lost!
  • Danger of Depth
    [Visualizing the Results of Multimedia Web Search Engines.
    Mukherjea, Hirata, and Hara. InfoVis 96]

3D vs. 2D Bar Charts

  • 🚫 3D bars🚫
    • Perspective distortion
    • Occlusion
  • 2D faceting 👌🏻

Tilted Text Isn’t Legible

Tilted Text
[Visualizing the World-Wide Web with the Navigational View Builder. Mukherjea and Foley. Computer Networks and ISDN Systems, 1995.]
  • Tilted text 👉 poor legibility

  • Further reading:
    [Exploring and Reducing the Effects of Orientation on Text Readability in Volumetric Displays.
Grossman et al. CHI 2007]

Power Demand of a Research Facility

Transform to New Data Abstraction

  • Derived data: cluster hierarchy
  • Juxtapose multiple views (calendar)
  • Superimposed 2D curves (clusters)

When to Use 3D

Shape perception

  • Benefits outweigh costs when target is shape

Why Shape Target
3D justified shape detection
[Image-Based Streamline Generation and Rendering. Li and Shen. IEEE Trans. Visualization and Computer Graphics (TVCG) 13:3 (2007), 630–640.]

Good Usage of 3D

Constrained navigation steps
through carefully designed viewpoints

When to Use 3D

  • Use 3D for true 3D spatial data. 👍
  • 3D needs very careful justification for abstract data.
    • Enthusiasm in 1990s, but now skepticism
    • Be especially careful with 3D for point clouds or networks
3D Node Link
[WEBPATH-a three dimensional Web history. Frecon and Smith. Proc. InfoVis 1999]

No Unjustified 2D

No Unjustified 2D

  • Consider whether network data requires 2D spatial layout
    • Especially if reading text is central to task!
    • Arranging as network means lower information density and harder label lookup compared to text lists
  • Benefits outweigh costs when topological structure/context important for task
    • Be especially careful for search results, document collections, ontologies
Target Networks

Do You Really Need a Map?

  • They use the position location
  • Use them for geographical tasks
  • Bad for comparison tasks
  • Don't use a map just because you have geo data

Eyes Beat Memory

Eyes Beat Memory

  • Principle: external cognition vs. internal memory
    • Easy to compare by moving eyes between side-by-side views
    • Harder to compare visible item to memory of what you saw

Eyes Beat Memory (cont.)

  • Implications for animation
    • Great for choreographed storytelling
    • Great for transitions between two states
    • Poor for many states with changes everywhere
      • Consider small multiples instead
Eyes beat memory

Example: Cerebral

  • Small multiples: one graph instance per experimental condition
    • Same spatial layout
    • Color differently, by condition
Cerebral
[Cerebral: Visualizing Multiple Experimental Conditions on a Graph with Biological Context. Barsky, Munzner, Gardy, and Kincaid. IEEE Trans. Visualization and Computer Graphics (Proc. InfoVis 2008) 14:6 (2008), 1253–1260.]

Why Not Animation?

  • Disparate frames and regions: comparison difficult
    • Vs. contiguous frames
    • Vs. small region
    • Vs. coherent motion of group
  • Safe special case
    • Animated transitions
Cerebral animation
[Cerebral: Visualizing Multiple Experimental Conditions on a Graph with Biological Context. Barsky, Munzner, Gardy, and Kincaid. IEEE Trans. Visualization and Computer Graphics (Proc. InfoVis 2008) 14:6 (2008), 1253–1260.]

Change Blindness

If attention is directed elsewhere, even drastic changes not noticeable

Resolution Beats Immersion

Immersive Visualization example
[Development of an information visualization tool using virtual reality. Kirner and Martins. Proc. Symp. Applied Computing 2000]
  • Immersion typically not helpful for abstract data
    • Do not need sense of presence or stereoscopic 3D
    • Desktop also better for workflow integration
  • Resolution much more important: pixels are the scarcest resource
  • Virtual reality for abstract data difficult to justify thus far
    • But stay tuned with second wave

Visualization Mantra

Visualization Mantra

  • Overview first, zoom and filter, then details on demand
  • Overview first, zoom and filter, then details on demand
  • Overview first, zoom and filter, then details on demand
  • Overview first, zoom and filter, then details on demand
  • Overview first, zoom and filter, then details on demand
  • Overview first, zoom and filter, then details on demand
  • Overview first, zoom and filter, then details on demand
  • Overview first, zoom and filter, then details on demand
  • Overview first, zoom and filter, then details on demand
  • Overview first, zoom and filter, then details on demand
[The Eyes Have It: A Task by Data Type Taxonomy for Information Visualizations. Shneiderman. Proc. IEEE Visual Languages, pp. 336–343, 1996.]

Overview

  • Overview 👉 summary
    • Microcosm of full visualization design problems
  • Useful for exploration
Why query summarize

Overview 👉 Zoom

TreeVersity2

Overview 👉 Filtering

TreeVersity2

Bottom-Up?

  • Sometimes makes sense to start small
  • Useful for presentation
  • Common in storytelling
  • Helps explaining complex concepts

Function First,
Form Next

Function First

  • Start with focus on functionality
    • Possible to improve aesthetics later on, as refinement
    • If no expertise, seek for help from graphic designers
  • Dangerous to start with aesthetics
    • Usually impossible to add function retroactively
[The Non-Designer’s Design Book. Robin Williams. 3rd edition. Peachpit Press, 2008.]

Aesthetics Do Matter

  • Another level of function
    • Visual hierarchy, alignment, flow
    • Gestalt principles in action
  • Very important for the enjoy task
[The Non-Designer’s Design Book. Robin Williams. 3rd edition. Peachpit Press, 2008.]

Responsiveness Is Required

Visual feedback: three rough categories
  • 0.1 seconds: perceptual processing
    • Subsecond response for mouseover highlighting: ballistic motion
  • 1 second: immediate response
    • Fast response after mouseclick, button press: Fitts’s Law limits on motor control
  • 10 seconds: brief tasks
    • Bounded response after dialog box: mental model of heavyweight operation (file load)

Scalability Considerations

  • Highlight selection without complete redraw of view (graphics frontbuffer)
  • Show ⏳ for multi-second operations (check for cancel/undo)
  • Show progress bar for long operations (process in background thread)
  • Rendering speed when item count is large (guaranteed frame rate)

Basic Design Principles

Basic Design Principles

  • Proximity
  • Alignment
  • Repetition
  • Contrast

Proximity

  • Do group related items together
  • Avoid equal whitespace between unrelated
Proximity
The Non-Designer’s Design Book, 4th ed. Robin Williams, Peachpit Press, 2015.

Alignment

  • Do find/make strong line, stick to it
  • Avoid automatic centering
Alignment
The Non-Designer’s Design Book, 4th ed. Robin Williams, Peachpit Press, 2015.

Repetition

  • Do unify by pushing existing consistencies
Repetition
The Non-Designer’s Design Book, 4th ed. Robin Williams, Peachpit Press, 2015.

Contrast

  • If not identical, then very different
  • Avoid similar
Contrast
The Non-Designer’s Design Book, 4th ed. Robin Williams, Peachpit Press, 2015.

Labels and Axis

Labeling

  • Make visualizations as self-documenting as possible
    • Meaningful and useful title, labels, legends
XKCD Labelling
https://xkcd.com/833/

Labeling (cont.)

  • Axes and panes/subwindows should have labels
    • And axes should have good mix/max boundary tick marks
  • Everything that’s plotted should have a legend
    • And own header/labels if not redundant with main title
  • Use reasonable numerical format
    • Avoid scientific notation in most cases

Avoid Dual Axis

  • Apples vs. oranges
  • Which one is which?

Be Careful with Aggregations

  • Mean vs. median
  • Show standard deviations
  • Show uncertainty
  • Does the aggregation make sense?
  • Cars and motorcycles have, on average, three wheels
  • Summing up grades (instead of averaging)

Normalize

  • When comparing, using a common metric
  • Usually percent
  • Always state percent to what

Ethics

Planned Parenthood
Alberto Cairo: How Charts Lie
Planned Parenthood
Alberto Cairo: How Charts Lie
Share of vote by county
Alberto Cairo: How Charts Lie
https://johnguerra.co/viz/USElections2016/
Citizens for Trump
Alberto Cairo: How Charts Lie
Popular vote barchart
Alberto Cairo: How Charts Lie
Popular vote including non voting
Alberto Cairo: How Charts Lie
Popular vote map
Alberto Cairo: How Charts Lie
Popular vote separated
Alberto Cairo: How Charts Lie
Map by electoral votes
Alberto Cairo: How Charts Lie

Thought exercise

Tasks:
  • T1. Identify the rate of job gains in the US in one specific month (Identify/Features)
  • T2. Compare the number of jobs gained on a month with the normal numbers (Identify/Features)
Ideas
  • Collect the number of jobs per month
  • Derive the difference of jobs to the previous month/week
  • Derive the % of new jobs with respect to the previous month/week
  • Visualize the % of new jobs
  • 👍 or 👎?
Trump's Job Gains Tweet
https://idsc.miami.edu/how-economic-data-has-been-distorted-during-covid-19/
Ny Times job Growth
https://www.nytimes.com/2020/10/02/business/economy/september-jobs-report.html
washington post job Growth
https://www.washingtonpost.com/business/2021/01/08/trump-jobs-record/

What We Learned

  • No unjustified 3D or 2D
  • Readable text
  • Eyes beat memory
  • Visualization mantra
  • Responsiveness is required
  • Function first, form next