Lecture 5

Question 1

So the variables of visual encoding are:

Answer 1

• Position
• Size
• Shape
• Brightness
• Color
• Orientation
• Texture
• Motion

Question 2

The application of graphics to communicate information requires an understanding of graphic primitives and their properties. For the most part, all graphic primitives will be termed

Answer 2

Marks

Question 3

Position

Answer 3

• First and most important visual variable
• It has the greatest impact on the audience
• A number of questions can be answered only by utilizing this variable wisely, like,
o Where do most of the data values fall?
o Does the data fit any well-known statistical distribution?
o Are there visible trends in the data?
o Are there any clusters within data?

Question 4

Mark/Shape

Answer 4

• The second visual variable is shape or mark: points, lines areas, volumes, and their composition.
• Any graphical object can be used as mark, including symbols, letters and words.
• The goal is to be able to easily distinguish between different marks quickly, while maintaining the overall view of the projected data space.
• Important:
It is important to consider how well one mark can be differentiated from the other marks.

Question 5

Size

Answer 5

• Size is :
o Third visual variable
o First graphic property
• Easily maps to interval and continuous data variables
Problem with size is the type of mark you choose.
o Works well with point, line and curves
o Does not work well with marks consisting of sufficient graphic area.

Question 6

Brightness

Answer 6

• Brightness is:
o Fourth visual variables
o Second graphic property
o Like size, it can be used to modify marks to encode the additional data variables.

Question 7

Human perception cannot distinguish between all pairs of brightness values True or False

Answer 7

True

Question 8

Color

Answer 8

The fifth variable is color.
Color can be defined by two parameters:
Hue: The dominant wavelength from the visual spectrum.
Saturation: Level of hue relative to gray, and drives the purity of color to be displayed.

Question 9

Orientation

Answer 9

The sixth visual variable is orientation or direction.
This graphic property displays how a mark is rotated in connection with a data variable.

Can be used with marks having natural single axis.
Cannot be used with marks having multiple axis or no axis like circle.

Question 10

Texture

Answer 10

The seventh visual variable is texture.

It can be considered as a combination of many of the other visual variables like marks, color and orientation.

Question 11

Motion

Answer 11

The eighth visual variable is motion.
It can be associated with any of the other visual variable, since the way a variable changes over time can convey more information.

Motion has the following two aspects:
Speed at which a change is occurring
Direction in which change is occurring like positive/negative