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