cs6630 September VISUAL ENCODING Miriah Meyer University of Utah

Transcription

1 cs6630 September VISUAL ENCODING Miriah Meyer University of Utah 1

2 administrivia... 2

3 - introducing Dr. Josh Levine 3

4 last time... 4

5 data abstraction the what part of an analysis that pertains to the data translation of domain-specific terms into words that are as generic as possible 5

6 type vs semantics 6

7 data types

8 dataset types

9 attribute types no implicit ordering meaningful magnitude, can do arithmetic Hierarchical

10 special attribute semantics key vs value

11 special attribute semantics key vs value flat tables multidimensional

12 special attribute semantics key vs value flat tables multidimensional fields

13 special attribute semantics temporal what makes time special?

14 DERIVED ATTRIBUTES - derived attribute: compute from originals - simple change of type - acquire additional data - complex transformation - transformation is abstraction choice 12

15 today... 13

16 - marks and channels - planar position - time - color 14

17 - marks and channels - planar position - time - color 15

18 MARKS -graphical element in an image -classified according to number of spatial dimensions required points (0D) lines (1D) areas (2D) 16

19 CHANNELS -parameters that control the appearance of marks 17

20 18

21 TYPES 19

22 MARK TYPES points (0D) lines (1D) areas (2D) 20

23 MARK TYPES marks as nodes (items) points (0D) lines (1D) areas (2D) 20

24 MARK TYPES marks as nodes (items) points (0D) lines (1D) areas (2D) marks as links containment 20 connection

25 CHANNEL TYPES 21

26 CHANNEL TYPES identity (what or where) magnitude (how much) 21

27 CHANNEL TYPES identity (what or where) magnitude (how much) 21

28 CHANNEL TYPES identity (what or where) magnitude (how much) 21

29 expressiveness & effectiveness 22

30 expressiveness

31 (how much) (what or where) expressiveness

32 effectiveness

33 name that channel... 25

34 26

35 WHERE DO RANKINGS COME FROM? 27

36 Bertin,

37 Mackinlay,

38 Cleveland & McGill,

39 Heer & Bostock,

40 DISCRIMINABILITY can channel differences be discerned? 32

41 33

42 SEPARABLE vs INTEGRAL - separable: can judge each channel individually - integral: two channels are viewed holistically separable integral 34 Ware 2004

43 SEPARABLE vs INTEGRAL 35 MacEachren 1995

44 SEPARABLE vs INTEGRAL separable integral color location color shape color motion size orientation x-size y-size red-green yellow-blue 36 Ware 2004

45 37

46 encoding semantics Ware

47 + perceptual effects we talked about last week - pop-out - Stevens power law - Weber s law - Gestalt principles 39

48 - marks and channels - planar position - time - color 40

49 WHAT S SO SPECIAL ABOUT THE PLANE? 41

50

51 we see the world as a 2.5D space 43

52 2.05D we see the world as a 2.5D space 43

53 2.05D we see the world as a 2.5D space 43

54 - power does not extend to 3D - perspective cues - interfere with color and size channels - occlusion of data - text legibility 44

55 45 Moore 2011

56 46

57 2D and 3D? 47 Keefe 2008

58 - marks and channels - planar position - time - color 48

59 visualization 1. uses perception to point out interesting things. 2. uses pictures to enhance working memory.

60 TIME AS ENCODING CHANNEL! - external versus internal memory - easy to compare views by moving eyes - hard to compare view to memory of what you saw 50

61 51

62 52

63 53

64 RECOMMENDED READING 54

65 WHEN TO USE ANIMATION? 55

66 GOOD: STORYTELLING 56

67 GOOD: TRANSITIONS 57

68 GOOD: TRANSITIONS 57

69 BAD: COMPARING COMPLEX STATE CHANGES OVER TIME 58

70 BAD: COMPARING COMPLEX STATE CHANGES OVER TIME 58

71 BAD: MULTIPLE STATES WITH MULTIPLE CHANGES 59

72 BAD: MULTIPLE STATES WITH MULTIPLE CHANGES 59

73 BAD: MULTIPLE STATES WITH MULTIPLE CHANGES alternative: small multiples 60 Barsky 2008

74 - marks and channels - planar position - time - color 61

75 Get it right in black and white. Maureen Stone 62

76 L6. Color REQUIRED READING 63

77 64

78 Color Most large animals have worse color vision than humans. Color vision is of little benefit to grass eaters like zebras and cows these animals have only two dimensions of color vision. The motion of a tiger s prey is more critical than its color, and although cats, like grazing animals, have the physiological basis for two dimensions of color, it is extremely difficult to train them to respond to color. For the most part, they behave as if they Color vision makes it much easier to see the fruit of the West African Akee tree