cs5984: Information Visualization Chris North Visualization Design cs5984: Information Visualization Chris North

Spotfire

Simple Visualization Model Data View Port Visual Mapping

Data Table Attributes Items (aka: cases, tuples, data points, …) Types: Quantitative Ordinal Nominal/Categorical Items (aka: cases, tuples, data points, …)

Visual Mapping Define a Space Map: data  marks Map: data attributes  graphical mark attributes Year  X Length  Y Popularity  size Subject  color Award?  shape

Ranking Visual Attributes Position Length Angle, Slope Size Color Increased accuracy for quantitative data -Cleveland

Visualization Design Process Primary Inputs: Data User Task Compare, known item search, patterns, outliers,… Scale # items dimensionality User characteristics Standards/guidelines System resources Bag of tricks: View types Interaction strategies Design Visualization

Design Principles 5 HCI Metrics: User performance *** Error rate User satisfaction Learning time retention

Interactivity Interaction to handle increased scale Direct Manipulation Visual representation Rapid, incremental, reversible actions Pointing instead of typing Immediate, continuous feedback Encourage exploration

Increase Data Density Calculate data/pixel “A pixel is a terrible thing to waste.”

Eliminate “Chart Junk” How much “ink” is used for non-data? Reclaim empty space (% screen empty) Attempt simplicity (e.g. am I using 3d just for coolness?)

Information Visualization Mantra Overview first, zoom and filter, then details on demand E.g. Spotfire

Query Previews http://www.cs.umd.edu/~egemen/demo.html

Data Space Multi-dimensional: databases,… 1D: timelines,… 2D: maps,… 3D: volumes,… Hierarchies/Trees: directories,… Networks/Graphs: web, communications,… Document collections: digital libraries,…

Assignment Read for Tues: Read for Thurs: Find some interesting data Inselberg “Multidimensional detective” (parallel coordinates) book p107 (margaret, josh s) Kandogan “Star Coordinates” web (matt c, fanye) Read for Thurs: Rao “Table Lens” p343,597 (marty e, purvi) Feiner “Worlds within Worlds” p96 (scott m, ?) Find some interesting data Send me your picture