1. Representing Data using Static and Moving Patterns Colin Ware UNH

2. Introduction Finding patterns is key to information visualization. Expert knowledge is about understanding patterns (Flynn effect) Example Queries: We think by making pattern queries on the world Patterns showing groups? Patterns showing structure? When are patterns similar? How should we organize information on the screen?

4. The dimensions of space

5. The “What” Channel Patterns of patterns

6. Two parts Part I: Static Patterns Part II: Patterns in Motion

7. Part I: Static Patterns Gestalt Laws [ Max Westheimer, Kurt Koffka, and Wolfgang Kohler (1912)] Proximity Similarity Continuity Symmetry Closure Relative Size Figure and Ground

8. Proximity Emphasize relationship by proximity Spatial Concentration a

9. Proximity

10. Similarity (Continued) Separable dimensionsIntegral dimensions

12. Connectedness Connectedness assumed in Continuity

13. Continuity Visual entities tend to be smooth and continuous

14. Continuity in Diagrams Connections using smooth lines

15. Graph aesthetics (experiment) a bx Continuity (inv bendiness) In

16. Results rt = -4.970 + 1.390spl + 0.01699con + 0.654cr + 0.295br spl: Shortest path length con: continuity cr: crossings br: branches 1 crossing adds.65 sec 100 deg. adds 1.7 sec 1 crossing == 38 deg.

17. Symmetry Symmetry create visual whole Prefer Symmetry

18. Symmetry (cont.) Using symmetry to show Similarities between time series data

19. Closure Prefer closed contours

20. Closure (cont.) Closed contours to show set relationship

21. Extending the Euler diagram

22. Closure (cont.) Segmenting screen Creating frame of reference Position of objects judged based on enclosing frame.

23. Relative Size Smaller components tend to be perceived as objects prefer horizontal and vertical orientations

24. Figure and Ground Symmetry, white space, and closed contour contribute to perception of figure.

25. Figures and Grounds (cont.) Rubin’s Vase Competing recognition processes

26. Field, Hayes and Hess Contour finding mechanisms

27. More Contours Direct application to vector field display

28. Vector fields Contours and pen strokes, 3D, shading

29. Vector Field Visualization Laidlaw

31. Evaluation Direction Magnitude Advection Global pattern Local pattern Nodal points

32. Algorithms Optimizing trace density (poisson disk) Flexible methods for rendering (enhanced particle systems).

33. Transparency Continuity is important in transparency x y > z y z > w

34. Laciness (Cavanaugh) Layered data: be careful with composites of textures

35. Patterns in Diagrams Patterns applied

36. Visual Grammar of diagrams

37. Semantics of structure

38. Treemaps and hierarchies Treemaps use areas (size) SP tree Graph Trees use connectivity (structure) www.smartmoney.com

39. Part II: Patterns in Motion How can we use motion as a display technique? Gestalt principle of common fate

40. Limitation due to Frame Rate Can only show motions that are limited by the Frame Rate. We can increase by using additional symbols.

41. Motion as a visual attribute (Common fate) correlation between points: frequency, phase or amplitude Result: phase is most noticeable

42. Motion is Highly Contextual Group moving objects in hierarchical fashion.

43. Frame as motion context The stationary Dot is perceived as moving in (a). The circle has no effect on this process in (b).

44. Using Causality to display causality Michotte’s claim: direct perception of causality

45. A causal graph

46. Michotte’s Causality Perception

47. Visual Causal Vectors

48. Experiment Evaluate VCVs Symmetry about time of contact.

49. Results Perceived effect

50. Motion Patterns that attract attention (Lyn Bartram) Motion is a good attention getter in periphery The optimal pattern may be things that emerge, as opposed to simply move. We may be able to perceive large field patterns better when they are expressed through motion (untested)

51. Anthropomorphic Form from motion Pattern of moving dots (captured from actor body) – Johansson. Attach meaning to movements (Heider and Semmel)

52. Conclusion Gestalt Laws are useful as design guidelines. Patterns should be present in luminance Patterns should be the appropriate size Motion is under-researched, but evidence suggest its power. Simple motion coding can be used to express communication, causality, urgency, happiness? (Braitenberg)