cs5764: Information Visualization Chris North 2-D Information Spaces cs5764: Information Visualization Chris North

Powers of 10 Charles & Ray Eames

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

2-D Image browsing Maps

2-D: large spaces http://terraserver.homeadvisor.msn.com/image.asp?S=10&T=1&X=2689&Y=20639&Z=17&W=2

Tasks?

Detail Only Typical image browser MS PhotoEditor Typical map browser mapquest.com

Zooming

Zooming: Pad++ Infinitely zoomable surface (Bederson et al.) Layout information in 2d+scale Interaction: pan+zoom Need more info? Just zoom in! Jazz

Pad++ examples Authored spaces (user specified layouts) E.g: filesystem replacement?, presentations, stories HiNote, Kidpad http://www.cs.umd.edu/hcil/jazz/play/ http://vtopus.cs.vt.edu/~north/infoviz/hinoteapplet.html Counterpoint: powerpoint with zooming http://www.cs.umd.edu/hcil/counterpoint/

Pad++ examples Automated layouts E.g: File system, web history

Pad++ examples In visualization

Space-Scale

Pad++ on edge Like ray-tracing Info surface zoom window

Semantic Zooming Zooming in, red object turns to blue label label

Good/Bad Good: Bad:

Good/Bad Good: Bad: “step back” to get overview “step forward” for more details Infinite space for more details Visual scale  conceptual scale Bad: lose context when zoom in Get lost

Overview+Detail

Overview+Detail Overview: Detail: Zoom factor = ? Square in overview coupled to scroll bars of detail

Multiple levels = large scale overview intermediate view intermediate view detail view Zoom factor = ?

Multiple Foci

Multiple Overviews Can have different data types in each view Color slice CaT scan

O+D vs Detail-Only Beard & Walker: 2D Chimera: trees North: 1D (lists) Scrollbars are bad!

Intermediate views? Plaisant, “When an Intermediate view matters” When >20x Overview ? Detail view

Focus+Context

Bifocal Display Leung, “Bifocal displays”

Document Lens Robertson, “Document Lens”

Moosburg moosburg.cs.vt.edu Wendy Schafer

Distortion Functions Mapping from info surface to display surface f Information surface Display surface

Visual Transfer Functions Display surface Display surface Information surface Information surface Identity function = normal flat overview Bifocal

Magnification Functions Bifocal 1st Derivative Magnification Magnification Information surface Information surface

Bifocal Display Disadvantage: 1 dimensional stretching on the 4 sides

Perspective Wall / Document Lens Context shrinks gradually Perspective

NonLinear Magnification http://www.cs.indiana.edu/hyplan/tkeahey/research/nlm/nlm.html http://www.cs.indiana.edu/hyplan/tkeahey/research/papers/infovis.98.html

“Bubble” Disadvantage: local context highly de-magnified Bubble

“Fisheye”, “wide-angle lens” Disadvantage: no flat area Wide-angle

Focus+Context Bifocal Perspective Bubble Wide-angle

Quiz: TableLens Bifocal!

Fisheye Menus

Calendar Leung

Why not magnifying glass? Hides local context

Focus+Context Screens Baudisch, “Keeping things in context…”

F+C vs. O+D + - + -

F+C vs. O+D + Scales up to larger data (zoom factor and chaining) + Multi foci easier + multiple overviews possible + Easy to implement, Less math! Fast system performance - >=2 places to look (cross-eyed!) Tracking field-of-view box hard Hand-eye coordination problem - detail and overview disconnected - Windows/space management - replicates detail data in overview + Space efficient + Detail connected to context Smooth transition + matches human vision/processing? (or fish?) + Neato! - Distortion - Longer learning time - no flat overview - Need a way to turn off focus - Content moves differently than mouse, “overshoot” problem - zoom factors usually small

Transparency Lieberman, “Macroscope: Powers of Ten Thousand”

2-D + Attributes Dynamaps: dynamic queries on maps

Navigation Strategies Detail only: detail without overview Zooming: detail becomes overview Overview+Detail: detail next to overview Focus+Context: detail within overview Transparency: detail on top of overview Focus+Context: “Distortion-oriented display” “Fisheye”