1. Cambridge, Massachusetts Perception of Elementary Graphical Elements in Tabletop and Multi-Surface Environments Daniel Wigdor, Chia Shen, Clifton Forlines, Ravin Balakrishnan CHI 2007 Department of Computer Science, University of Toronto

2. Acknowledgements John Barnwell John Hancock MERL & DGP Lab members Experiment participants

5. In-Plane Rotation

6. NOT THIS PAPER

7. Planar Rotation

15. Information Graphics

17. Encoding & Decoding 1528 2352

18. Encoding & Decoding 1528 2352 Encode

19. Encoding & Decoding 1528 2352 Encode Decode

20. *

21. Cleveland and McGill: Elementary Perceptual Tasks Bertin: Visual Variables

22. Visual Variables

23. Colour

24. Visual Variables Colour

25. Visual Variables Colour

26. Visual Variables Colour

27. Visual Variables Colour Position

28. Visual Variables Colour Position

29. Visual Variables Colour Position Slope

30. Visual Variables Colour Position Slope

31. Visual Variables Colour Position Slope

32. Visual Variables Colour Position Slope

33. Visual Variables Colour Position Slope

34. Visual Variables Colour Position Slope Length

35. Visual Variables Colour Position Slope Length

36. Visual Variables Colour Position Slope Length

37. Visual Variables Colour Position Slope Length Area

38. Visual Variables Colour Position Slope Length Area

39. Visual Variables Colour Position Slope Length Area Angle

40. Visual Variables Colour Position Slope Length Area Angle

41. Visual Variables Colour Position Slope Length Area Angle

42. Visual Variables Colour Position Slope Length Area Angle

43. Visual Variables Colour Position Slope Length Area Angle Modulus:

44. Visual Variables Colour Position Slope Length Area Angle Modulus: Stimulus:

45. Visual Variables Colour Position Slope Length Area Angle Modulus: Stimulus: Answer: 38%

46. Visual Variables Colour Position Slope Length Area Angle Modulus: Stimulus: Answer: 38%

47. Visual Variables Colour Position Slope Length Area Angle

48. Visual Variables Colour Position Slope Length Area Angle Modulus:

49. Stimulus: Visual Variables Colour Position Slope Length Area Angle

50. Modulus: Stimulus: Answer: 40% Visual Variables Colour Position Slope Length Area Angle

51. Modulus: Stimulus: Answer: 40% Visual Variables Colour Position Slope Length Area Angle

52. Visual Variables Colour Position Slope Length Area Angle

53. Modulus: Visual Variables Colour Position Slope Length Area Angle

54. Modulus: Stimulus: Visual Variables Colour Position Slope Length Area Angle

55. Modulus: Stimulus: Answer: 67% Visual Variables Colour Position Slope Length Area Angle

56. Modulus: Stimulus: Answer: 67% Visual Variables Colour Position Slope Length Area Angle

57. 57 Poor Elementary Perception

58. 58 Slope vs Position

59. 59 Slope vs Position

60. Experimental Task (Cleveland & McGill)

64. Conclusions (Cleveland & McGill) Error correlated with distance Rank order of elementary tasks: 1.Position, common scale 2.Position, identical nonaligned scales 3.Length 4.Angle 5.Slope 6.Area 7.Volume, Density, Colour saturation 8.Colour hue

65. Graphical Perception on a Rotated Plane Vs.

66. Our Visual Variables:

67. Experimental Task Example: Line Length

68. Experiment 1: Single-Screen Comparisons 90° (Vertical) 60° 30° 0° (Tabletop)

72. Hypotheses I. As the display is tilted, the accuracy of relative magnitude judgements decreases.

73. Hypotheses I. As the display is tilted, the accuracy of relative magnitude judgements decreases. Error Display Angle Vertical Tabletop

74. Hypotheses II. The up/down distance between objects is positively correlated with the increase in error in magnitude judgements due to screen angle. Up/Down Distance ERROR

75. Hypotheses II. The up/down distance between objects is positively correlated with the increase in error in magnitude judgements due to screen angle. Tabletop Vertical

76. Hypotheses III. Different visual variable types have differing increases in the error in judgements.

77. Hypotheses III. Different visual variable types have differing increases in the error in judgements.

78. Hypotheses IV. Sideways presentations of objects experience less error in magnitude judgements due to screen angle than upright presentations.

79. Hypotheses IV. Sideways presentations of objects experience less error in magnitude judgements due to screen angle than upright presentations. Error

80. Hypotheses V. There will be no effect for side-to-side distance on the accuracy of magnitude perception. Side-to-side Distance

81. Hypotheses V. There will be no effect for side-to-side distance on the accuracy of magnitude perception. Side-to-side Distance

82. slope area position length angle Rank Ordering of Visual Variable Perceptibility Vertical Ranking: Tabletop Ranking:

83. position (upright) length (upright) angle (upright) slope area position (sideways) length (sideways) angle (sideways) position (upright) length (upright) angle (upright) slope area position (sideways) length (sideways) angle (sideways) length (upright) angle (upright) slope area position (sideways) length (sideways) angle (sideways) position (upright) Rank Ordering of Visual Variable Perceptibility Vertical Ranking: Tabletop Ranking:

84. Multi-Surface Environments

85. Experiment 2: Apparatus

86. Hypotheses I.There is an increase in error when comparing visual variable magnitudes between upright and tabletop displays versus comparing on displays of a single orientation.

87. Hypotheses I.There is an increase in error when comparing visual variable magnitudes between upright and tabletop displays versus comparing on displays of a single orientation.

88. Hypotheses II.The error increase when comparing between displays is unevenly distributed across visual variable types.

89. Hypotheses II.The error increase when comparing between displays is unevenly distributed across visual variable types.

90. Hypotheses III.The size of the error on the mixed-orientation condition is larger than the largest errors in the previous experiment.

91. Hypotheses III. The size of the error on the mixed-orientation condition is larger than the largest errors in the previous experiment.

92. Recommendations Mixed-orientation screen comparisons are hard Ordered list (different than before): 1.length (sideways) 2.length (upright) 3.position (sideways) 4.angle (sideways) 5.area 6.angle (upright) 7.position (upright) 8.slope

93. Conclusions Don’t compare across display orientations Special visualisations for tabletops & multi-surface spaces

94. Future Work Σ = ?

95. Questions?

96. Experiment 1 Design 12 participants x 4 display angles x 4 visual variables (per participant) x 3 modulus positions x 9 stimulus positions x 3 magnitude estimates = 15,552 total comparisons

97. Experiment 2 Design 8 participants x 2 display angles x 8 visual variables x 31 magnitude estimates = 3,968 total comparisons