Semiology of Visualization CMSC 436/636
Data Visualization
Penny Rheingans University of Maryland Baltimore County
Bertin: Semiology of Graphics Fundamental graphic variables ◦ Location ◦ Size ◦ Value (brightness) ◦ Texture/grain ◦ Color ◦ Orientation ◦ Shape
Rules for appropriate use
MacEachren on Bertin Additional variables ◦ Arrangement ◦ Texture density ◦ Saturation ◦ Transparency ◦ Crispness ◦ Temporal variation ◦ Touch: multiple ◦ Sound: multiple
Basic Scalar Techniques Height Mapping Density/Opacity Size Color Texture
Preattentive Processing
What properties of objects easily perceived by the HVS? ◦ Serial search ◦ Parallel search -> preattentive
Tasks ◦ Target detection ◦ Boundary detection ◦ Region tracking ◦ Counting and estimation
Preattentive Processing
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Target Detection
Preattentive Processing
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Boundary Detection
Preattentive Processing
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Counting and Estimation
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Hue
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Luminance
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Orientation
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Length
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Size
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Curvature
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Closure
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Intersection
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Termination
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Density
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
3D Depth
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
3D Light
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
3D Orientation
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Direction
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Flicker
Preattentive Features
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Velocity
Preattentive Processing
Issues ◦ Conjunctions ◦ Distractions
Healey, www.csc.ncsu.edu/faculty/PP/index.html
Preattentive Processing
Feature Hierarchy ◦ Hue > form ◦ Luminance > hue ◦ Hue > texture ◦ Distractions on the hierarchy
Example http://www.csc.ncsu.edu/faculty/healey/PP/index.html