- Value (saturation/opacity)
Two types of retinal variables:
Scale of measurement for each variable:
- An associative variable does not affect the visibility of other dimensions (e.g. we can recognize color regardless of orientation.)
Hue, Orientation, Texture, Shape, Position are associative.
- A dissociative variable significantly affect the visibility of other dimensions (e.g. its hard to determine color of a thin line or small dot).
Size and Value are dissociative (they dominate perception and disrupt processing of other correlated dimensions)
- Categorical: Distinct categories should be obvious. For example, different states, jobs, or students.
Which variables can be used for categorical scale?
- Ordered: Determine relative ordering. For example, you rate your professor on the scale: good, medium, bad
Position, size, and value are ordered
- Quantitative: Determine amount of difference between
ordered values. For example, family income in US dollars.
Position and size are quantitative
Color brewer is a good resource for color selection: http://colorbrewer2.org/
Tables/images on this page are retrived from textbooks. Some were adapted from Visualization and Visual Analytics class at UIC by Prof. Andrew Johnson.
© Last revised: Oct 19th, 2016