1D & 2D Spaces for Representing Data

Mao Lin Huang

1-D Representation of Data

1-D Textual Data

Keyhole Problem• No context• Lost, disoriented

• Where am I?• Where can I go?• Where do I want to go?• How do I get there?

Visual Overview• Map, organization (spatial layout of concepts)

• What information is (not) available?• Adds context info, relationships• Enables direct access• Encourages exploration• HCI metrics:

• Improves user performance, learning time, error rates, retention, satisfaction

Navigation Approaches• Detail Only

• Zooming

• Overview+Detail

• Focus+Context (Distortion, fisheye)

1D Visual Representation• Plaisant, “Lifelines”, pp 285

See personal history

• Mackinlay, “Perspective Wall”, web

1D Visual Representation• Eick, “SeeSoft”, p 419

» Analyze 50,000 lines of code simultaneously by mapping each line of code into a thin row.

• Eick, “Data Visualization Sliders”, p 251 (2 pages)

Navigation Strategies• Detail Only

• Zooming

• Overview+Detail

• Focus+Context (Distortion, fisheye)

Fisheye Menus• http://www.cs.umd.edu/hcil/fisheyemenu/

• Very Fast• due to mouse mechanics, no clicking, mostly vertical sliding

• Alphabet overview helpful• Fisheye context not useful in this case?

• Might be more useful in SeeSoft where miniature representation gives important information

• Limits # of readable items to ~10• Wasted space at top- and bottom- right• Distortion problematic?• Alphabet overview distorted at A and Z• Scale limited?

• Possible improvement:• Same alphabet overview (without end distortion)• Remove fisheye, maximize readable items like scrolling

version• Same fast mouse mechanics, scroll fast on left, no scroll on

right

Music Animation Machine

• Good for visualizing music during serial playback, relate audio to visual structure

• Visualizing entire compositions: increase information density

• See patterns of phrases, instruments, etc.

2-D Representation of Data

2-D• Image browsing• Maps

Today• Bederson, “Pad++”, p 530

» a zooming graphic interface to replace icon-based window interface

• Furnas, “Space-Scale Diagrams”, web

Space-Scale

Pad++ on edge• Like ray-tracing Info surface

window

zoom

Semantic Zooming• Zooming in, red object turns to blue

Multiple Views• Zoom factor ~ 20

Multiple levels = large scale• Zoom factor = 20 * 20 * 20 = 8000

Multiple Foci

Multiple Overviews• Can have different information types at each level

2-D + Attributes• Dynamaps: dynamic queries on maps

2-D: Focus+Context Representation of Data

2-D• Robertson, “Document Lens”, p 562

»

• Spence, “Bifocal Lens”, p 331,333

Focus+Context• Details within overview

• “Distortion-oriented display”• “Fisheye”

• Leung, Apperley, “Taxonomy of distortion-oriented presentations”, book pg 350

Visual Transfer Functions

Information surface

Display surface

Identity function = normal flat overview

Bifocal

Magnification Functions

1st Derivative

Bifocal Display• Spence, Apperley

Bifocal DisplayDisadvantage: 1 dimensional stretching on the 4 sides

Perspective Wall / Document Lens

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

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

Quiz: TableLens

• Bifocal!

Fisheye Menus• Non-linear:

combination of Bubble + fisheye

Why not magnifying glass?• Hides local context

F+C vs. O+D

• + Space efficient• + Detail connected to context

• Smooth transition• + matches human vision/processing?

• - Distortion• - Longer learning time• - no flat overview - Need a way to

turn off focus• - Content moves differently than

mouse• - hard to tell zoom factor

• + 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