1. Python Review

2. Iteration Start Stop Increment Number for x in sequence: print x
Start: x = sequence[0]
Stop: x = sequence[len(sequence) – 1]
Increment: values in sequence
Number: len(sequence)

3. Iteration Start Stop Increment Number for x in range(10): print x
Start: x = 0
Stop: x = 9
Increment: 1
Number: 10

4. Iteration Start Stop Increment Number for x in range(0, 12, 2):
print x
range(0, 12, 2)  [0, 2, 4, 6, 8, 10]
Start: x = 0
Stop: x = 10
Increment: 2
Number: 6

5. Iteration Start Stop Increment Number x = 0 while x <= 10: print x
x = x + 2
Start: x = 0
Stop: x > 10
Increment: 2
Number: 6

6. Iteration x = 0 x = 0 while x <= 10: while x <= 10: print x
Go Forever
x = 0
while x <= 10:
x = x + 2
print x
while x <= 10:
x = 0
print x
x = x + 2
All Zeros

7. Color in Visualization
CMSC 120: Visualizing Information
Lecture 4/24/08

8. Multivariate Visualization
3 or more dimensions hard to visualize
Projection into lower-d space distorts data
Multifunctioning Graphical Elements

9. Color Pre-attentive 1000s of different colors 20-30 gray tones
Patterns, boundaries, movement

10. Color Purposes Emphasis Appeal Dimensionality
Hello, here is some text. Can you read what it says?
Hello, here is some text. Can you read what it says?
Hello, here is some text. Can you read what it says?
Hello, here is some text. Can you read what it says?
Hello, here is some text. Can you read what it says?
Hello, here is some text. Can you read what it says?

12. Color

13. Color
The quality of an object with respect to the light reflected by the object
Determined visually by:
Hue: color
Saturation: purity
Brightness: % black

14. Color

15. Types of Colors Additive Colors Subtractive
All visible colors are a sum of two or more
Primary Colors
Red, Green, Blue
Subtractive
Complementary Colors
Removing an additive color from white light

16. Representing Color
Encoding
RGB
CMKY = 1 - RGB

17. Choosing the Right Color
Human matches colors
Addition of pattern elements
<
> 20 can no longer be pre-attentively processed
VGA Monitor
16 colors
262,144 (643)
Super VGA
256 colors
Several million
How much and which colors?

18. Color Schemes

19. Color Schemes
Color may carry standardized meanings in particular applications.
blue = water bodies
green = vegetation
brown = desert/mountains
white = ice or snow, etc.
Color maps

20. 2004 Election

21. Tornado

22. Elevational map of Kansas
Similar colors: subclasses
Dissimilar: barriers/unrelated

23. Complementary Colors Opposites on the color wheel High Contrast
Vibrant (full saturation)
Can be jarring
Make something stand out
Bad for text

24. Analogous Colors Adjacent on Color Wheel Serene Comfortable
Found in Nature
Pleasing
Contrast can be problematic
Use black, white, gray as an accent

25. Analogous Colors Adjacent on Color Wheel Serene Comfortable
Found in Nature
Pleasing
Contrast can be problematic
Use black, white, gray as an accent

26. Triadic Colors Evenly spaced Vibrant, even when pale hues are used
Balance color use
One dominate
Others accent

27. Warm and CoolColors Cool colors Hot colors Short wave length
violet, blue, cyan, green
large regions
features for which no special emphasis is desired
Hot colors
Long wavelength
yellow, orange, red, magenta (long wavelength).
Best used for small regions
features for which special emphasis is desired

28. Hot and Cool Colors Color Stereoscopic Effect
cool colors appear farther away
hot colors appear closer.
enhanced by using black boundaries between color areas, a small contour interval, and bright high-saturation or fluorescent