CDS 6324 - Data Visualization

Lecture 8: Interactive Visualization (Animation & Motion)

1. Why Use Motion & Animation?

Motion and animation are used to encode information, direct attention, explain transitions, and increase engagement.
🧠 Animation = Attention + Transition + Engagement

2. Motion Perception

Motion perception refers to how humans detect and interpret movement.
Humans can typically track only about 4–6 moving objects simultaneously.
Exam Keyword:
Multiple Object Tracking

3. Principle of Common Fate

Objects moving in the same direction and speed are perceived as belonging to the same group.
A collection of dots moving together is naturally interpreted as one object or cluster.
🧠 Same Motion → Same Group

4. Biological Motion

Humans can recognize motion patterns even from a few moving points.
Johansson (1973) attached lights to human joints. Observers immediately recognized a walking person despite seeing only moving dots.
Motion alone can communicate structure and identity.

5. Motion Shows Transitions

Animation helps viewers understand how one state changes into another.
Potential Issues:
Too fast → confusion
Too slow → boredom
Too many moving objects → overload

6. Constructing Narratives

Humans naturally create stories from moving objects.
In the Heider-Simmel experiment (1944), participants watched moving shapes. Most viewers interpreted them as characters with intentions and emotions.
Motion can imply goals, relationships and storytelling.

7. Perception of Causality

Certain motion patterns create the impression that one object causes another object to move.
Effect Description
Launching Effect One object appears to hit another object
Entraining Effect One object appears to carry another object

8. What is Animation?

Animation is the act of bringing visual elements to life through movement.
Characteristic Benefit
Attention Draws viewer focus
Object Constancy Preserves identity during changes
Causality Suggests relationships
Engagement Makes visualization more interesting

9. Principles of Animation

Tversky (2002) proposed two key principles for effective animation.
Principle Meaning
Congruence Animation should match the intended message
Apprehension Animation should be easy to perceive and understand
🧠 Congruence = Correct Meaning
Apprehension = Easy Understanding

10. Three Uses of Animation

Use Purpose
Animation as Narrative Tells a story
Animation as Encoding Represents data values
Animation as Transition Shows changes between states
Exam Favorite:
Narrative, Encoding, Transition

11. Taxonomy of Transitions

Different types of animated transitions help users understand changes.
  1. Transformation of View
  2. Change of Representation
  3. Transformation of Surface
  4. Timestep
  5. Change of Data Structure
  6. Reordering
  7. Filtering

12. 10 Principles of Animated Transitions

Congruence Principles

  1. Respect semantic correspondence
  2. Avoid ambiguity
  3. Maintain valid graphics during transition
  4. Maintain valid mappings across graphics

Apprehension Principles

  1. Group similar transitions
  2. Minimize occlusion
  3. Maximize predictability
  4. Use simple transitions
  5. Stage complex transitions
  6. Make transitions as long as needed, but not longer

13. Animation in Statistical Charts

IBM Design recommends animations should be:
🧠 UEICC
Understandable → Essential → Impactful → Consistent → Contextual

14. Does Animation Help?

Benefits Risks
Direct attention Can distract viewers
Track changes May imply false relationships
Show cause and effect May imply false causality
Increase engagement May become chart junk
Preserve object constancy Too fast or too slow hurts understanding
Key Exam Idea:
Animation is useful only when it improves understanding. Decorative animation becomes chart junk.

15. Final Exam Summary

Most Important Points

  • Motion: Directs attention and explains change.
  • Common Fate: Objects moving together are grouped together.
  • Animation Principles: Congruence and Apprehension.
  • Three Uses: Narrative, Encoding, Transition.
  • Transition Types: View, Representation, Surface, Time, Structure, Reordering, Filtering.
  • 10 Principles: Ensure animations remain understandable.
  • Animation Tradeoff: Can improve understanding or become chart junk.