Animation. Yuyi Zhou Nov 16

Transcription

1 Yuyi Zhou Nov 16

2 Animation: Can It Facilitate? Barbara Tversky, Julie Morrison, Mireille Betrancourt, International Journal of Human Computer Studies 57:4, pp , 2002 Interactive Visualization of Genealogical Graphs Michael J. McGuffin, Ravin Balakrishnan. Proc. InfoVis 2005, pp

3 Animation: Can It Facilitate? Evaluate Animation from: Two principles to make effective graphics: Congruence Principle: The structure and content of the external representation should correspond to the desired structure and content of the internal representation. Apprehension Principle: The structure and content of the external representation should be readily and accurately perceived and comprehended.

4 Congruence principle Animation: Can It Facilitate? Animation graphics: Convey concepts of change. - In principle, it should be effective for expressing changes. Selectively review research on animation -- aim to find out if animation facilitate conveying complex system (ie. mechanical, biological, physical, operational, computational) compared to static graphics.

5 Congruence principle Animation: Can It Facilitate? Yet, animation has not produced the expected benefits. Animated graphics must be compared to informationally equivalent static graphics. Many of studies conclude animations is better : - lack of equivalent information in static and animated graphics. - benefit from interactivity rather than animation - use prediction to facilitate learning Animation fail to benefit learning

6 Apprehension principle Animation: Can It Facilitate? The drawback of animation is the perceptual and cognitive limitations in the processing of a changing visual situation Animation may be hard to perceive. -- complex interactions simply happened too fast to be accurately apprehended. Animation may be comprehended discretely -- people conceive motions in discretely steps instead of continuously. -- difficult to perceive all the minute changes simultaneously.

7 Implications Animation: Can It Facilitate? Animation must be used with care: - If there are benefits to animation, they should be evident especially for continuous rather than discrete changes. - Whether animations are more effective than static graphics for the subtle aspects of change of time is unknown. - Interactivity may be the key to overcoming the drawbacks of animation as well as enhancing its advantages.

8 Interactive Visualization of Genealogical Graphs Difficult to draw genealogical graphs: - Contains many long edges - Doesn't show clearly which nodes are in the same generation - Many lines of ancestry and descent have been omitted

9 Interactive Visualization of Genealogical Graphs Existed diagramming software - Users must repeatedly and manually move increasingly large subsets of nodes to create room for new data - It's not clear that displaying entire genealogical graphs of thousands of nodes would be ideal, since numerous long edges or edge crossings would make navigation and interpretation difficult. Solution proposed by this paper - Develop dual-tree scheme that generalizes hourglass charts - Display subgraphs that are automatically laid out, and allow users to flexibly transition between subgraphs.

10 Interactive Visualization of Genealogical Graphs Dual Tree: an union of an ancestor tree and a descendant tree. It can be drawn with no edge crossings, with nodes ordered by generation, and it scales relatively well. Interaction Techniques: Transition between different dual-tree subsets: - Expanding/collapsing parents/children of a given node Rotation caused by expanding a node, other nodes collapsed may be required to maintain the dual-tree scheme. Expansion, collapsing and rotation of nodes is shown with smooth, 1-second animations to help the user maintain context.

11 Interactive Visualization of Genealogical Graphs Video demo of genealogy vis:

12 Critique Animation: Can It Facilitate? Partially agree with the view that static graphics are better than animation to convey information in some situations. Disadvantages of animation is strongly proved by using many studies, while advantages of animation is addressed much less words on. Bias on animation?.

13 Critique Interactive Visualization of Genealogical Graphs It shows the situation where animation should be adopted instead of static graphics. Display a subset of a large graphs, with the help of animation, dual-tree can keep its scheme by rotation, users can interactively transition from subset to subset and browse the entire tree. It s a brilliant idea to do visualization this way in this situation.

14 Questions?