1. Lecture 06: Design II February 5, 2013 COMP 150-2 Visualization

2. Admin A2: No need to handle negative values Go over the bit shifting and bit masking examples in backbuffer isect example Meeting with your TA before the due date of the next assignment! Liz announcement EC1 graded Design Lecture by Dan Kass

3. Edward Tufte The Visual Display of Quantitative Information Self-published book Evangelist for good visual design Most designs are static, but many principles apply to interactive (computer-based) visualization designs Take these design guidelines with a grain of salt

4. Graphical Excellence Tuftes Principles of Graphical Excellence 1.Graphical excellence is the well-designed presentation of interesting data – a matter of substance, of statistics, and of design.

5. Graphical Excellence Tuftes Principles of Graphical Excellence 1.Graphical excellence is the well-designed presentation of interesting data – a matter of substance, of statistics, and of design. 2.Graphical excellence consists of complex ideas communicated with clarity, precision, and efficiency.

6. Graphical Excellence Tuftes Principles of Graphical Excellence 1.Graphical excellence is the well-designed presentation of interesting data – a matter of substance, of statistics, and of design. 2.Graphical excellence consists of complex ideas communicated with clarity, precision, and efficiency. 3.Graphical excellence is that which gives to the viewer the greatest number of ideas in the shortest time with the least ink the smallest place.

7. Graphical Excellence Tuftes Principles of Graphical Excellence 1.Graphical excellence is the well-designed presentation of interesting data – a matter of substance, of statistics, and of design. 2.Graphical excellence consists of complex ideas communicated with clarity, precision, and efficiency. 3.Graphical excellence is that which gives to the viewer the greatest number of ideas in the shortest time with the least ink the smallest place. 4.Graphical excellence is nearly always multivariate

8. Graphical Excellence Tuftes Principles of Graphical Excellence 1.Graphical excellence is the well-designed presentation of interesting data – a matter of substance, of statistics, and of design. 2.Graphical excellence consists of complex ideas communicated with clarity, precision, and efficiency. 3.Graphical excellence is that which gives to the viewer the greatest number of ideas in the shortest time with the least ink the smallest place. 4.Graphical excellence is nearly always multivariate 5.And graphical excellence requires telling the truth about the data.

9. Napoleons March to Moscow

10. Minards Map of Napoleons March to Moscow

11. Graphical Integrity Above all else show the data

12. The Lie Factor Tufte coined the term the lie factor, which is defined as: Lie_factor = High lie factor (LF) leads to: Exaggeration of differences or similarities Deception Misinterpretation

13. The Lie Factor The Lie Factor (LF) can be LF > 1 LF < 1 If LF is > 1, then size of graphic is greater than the size of data This leads to exaggeration of the data (overstating the data) If LF < 1, then the size of the data is greater than the graphic This leads to hiding the of data (understating the data)

14. Whats Wrong With This? US Department of Transportation had set a series of fuel economy standards to be met by automobile manufacturers, beginning with 18 miles per gallon in 1978 and moving in steps up to 27.5 by 1985.

15. Whats Wrong With This? This line represents 18 miles per gallon in 1976, is 0.6 inches long This line represents 27.5 miles per gallon in 1985, is 5.3 inches long

16. Whats Wrong With This?

17. Similarly This design contains a lie factor of 9.4

18. Similarly This design contains a lie factor of 9.5

19. Other Ways To Lie (with the legend)

20. Other Ways To Lie (with the encoding)

21. Other Ways To Lie (with the design variation)

22. Beware of the 3D effect. It distorts the telling of the data. There are five vertical scales here: 1073-1978: 1 inch = $8.00 Jan-Mar: 1 inch = $4.73 Apr – Jun 1 inch = $4.37 Jul – Sep 1 inch = $4.16 Oct – Dec 1 inch = $3.92 And two horizontal scales: 1973-1978: 1 inch = 3.8 years 1979 1 inch = 0.57 years

23. Other Ways To Lie (with the design variation) The 3D chart capability in Excel:

24. Other Ways To Lie (with double-encoding, e.g. size) Here, both width and height encode the same information. The effect is multiplicative. 0.44 (width) * 0.44 (height) = 0.19

25. Other Ways To Lie (with unintended encoding)

26. Are we encoding height, area, or volume?

27. Other Ways To Lie (with alignment)

28. Other Ways To Lie (with limited context)

33. Questions?

35. Design Principles for Graphical Integrity 1.The representation of numbers, as physically measured on the surface of the graphic itself, should be directly proportional to the numerical quantities represented. 2.Clear, detailed, and thorough labeling should be used to defeat graphical distortions and ambiguity. Write out explanations of the data on the graphic itself. Label important events in the data. 3.Show data variation, not design variation. 4.The number of information-carrying (variable) dimensions depicted should not exceed the number of dimensions in the data. 5.Graphics must not quote data out of context.

36. Design Principles for Graphical Integrity 1.The representation of numbers, as physically measured on the surface of the graphic itself, should be directly proportional to the numerical quantities represented. 2.Clear, detailed, and thorough labeling should be used to defeat graphical distortions and ambiguity. Write out explanations of the data on the graphic itself. Label important events in the data. 3.Show data variation, not design variation. 4.The number of information-carrying (variable) dimensions depicted should not exceed the number of dimensions in the data. 5.Graphics must not quote data out of context.

37. Design Principles for Graphical Integrity 1.The representation of numbers, as physically measured on the surface of the graphic itself, should be directly proportional to the numerical quantities represented. 2.Clear, detailed, and thorough labeling should be used to defeat graphical distortions and ambiguity. Write out explanations of the data on the graphic itself. Label important events in the data. 3.Show data variation, not design variation. 4.The number of information-carrying (variable) dimensions depicted should not exceed the number of dimensions in the data. 5.Graphics must not quote data out of context.

38. Design Principles for Graphical Integrity 1.The representation of numbers, as physically measured on the surface of the graphic itself, should be directly proportional to the numerical quantities represented. 2.Clear, detailed, and thorough labeling should be used to defeat graphical distortions and ambiguity. Write out explanations of the data on the graphic itself. Label important events in the data. 3.Show data variation, not design variation. 4.The number of information-carrying (variable) dimensions depicted should not exceed the number of dimensions in the data. 5.Graphics must not quote data out of context.

39. Design Principles for Graphical Integrity 1.The representation of numbers, as physically measured on the surface of the graphic itself, should be directly proportional to the numerical quantities represented. 2.Clear, detailed, and thorough labeling should be used to defeat graphical distortions and ambiguity. Write out explanations of the data on the graphic itself. Label important events in the data. 3.Show data variation, not design variation. 4.The number of information-carrying (variable) dimensions depicted should not exceed the number of dimensions in the data. 5.Graphics must not quote data out of context.

40. Data-Ink Maximize the Data-Ink Ratio

41. The Concept of Data-Ink Ratio Data-Ink Ratio =

42. Data-Ink Ratio The goal is to aim for high data-ink ratio Ink used for he data should be relatively large compared to the ink in the entire graphic Can be thought of as: proportion of a graphics ink devoted to the non-redundant display of data-information. Or, 1.0 – proportion of a graphic that can be erased without loss of data-information.

43. High Data-Ink Ratio Example

44. Low Data-Ink Ratio Example

45. Example Above, Improved Data-Ink Ratio of 0.7

46. Example Above, Going to Far… Data-Ink Ratio of 0.0

47. Within Reason Maximize the Data-Ink Ratio, within reason. Erase non-data-ink, within reason.

48. Erasing Non-Data-Ink? Multiple encodings: 1.Height of the left line 2.Height of the right line 3.Height of shading 4.Position of top horizontal line 5.Position (placement) of the number 6.Value of the number

49. Erasing Non-Data-Ink? Common statistical graphs

50. Erasing Non-Data Ink? Symmetry has its values…

51. Redundancy

52. Making the map into a 24 hour cycle adds redundancy, but improves usability

53. Redundancy

55. Application of Editing Results of a study indicating that one type of element always has a higher value under different experimental conditions

56. Application of Editing After removing all non- data carrying ink

57. Application of Editing The Ink that has been removed

58. The Process of Removing

59. Another Example The atomic volume as a function of the atomic number

60. Removing Unnecessary Ink

61. First Insight

62. Continuing the Removal

63. Problem… Removing the connecting lines decreases the sense of periodicity… Lets try adding in the grid again to see what happens

64. Redesign, Trial 1

65. Final Product

66. Questions?

67. Design Principles Based on Data-Ink Ratio 1.Above all else show the data 2.Maximize the data-ink ratio 3.Erase non-data-ink 4.Erase redundant data-ink 5.Revise and edit

68. Chart Junk Non-data-ink or redundant data-ink

69. Discussion Why is Chartjunk bad? Is it always bad?

70. Chart Junk vs. Memory Bateman et al. Useful Junk? The Effects of Visual Embellishment on Comprehension and Memorability of Charts, CHI 2010

71. Chart Junk vs. Memory

72. Eye Gaze

73. Results

75. Emphasis on Data, Not Graphic Dont do things just because you can. Do them because they are useful.

76. The Duck!

77. Questions?