2-D: Focus+Context

cs5984: Information Visualization

Chris North

Strategies

• Detail only: detail without overview• Zooming: detail becomes overview• Transparency: detail on top of overview• Overview+Detail: detail next to overview• Focus+Context: detail within overview

• Focus+Context:• “Distortion-oriented display”• “Fisheye”

Wendy Schafer

• Moosburg

moosburg.cs.vt.edu

Document Lens

• Robertson, “Document Lens”, p 562• priya, parool

Bifocal Display

• Leung, “Bifocal displays”• alex, qiang

Distortion Functions

• Mapping from info surface to display surface

f

Information surface Display surface

Visual Transfer Functions

Information surface

Display surface

Identity function = normal flat overview

Bifocal

Information surface

Display surface

Magnification Functions

1st Derivative

Bifocal

Information surface

Magnification

Information surface

Magnification

Bifocal DisplayDisadvantage: 1 dimensional stretching on the 4 sides

Bifocal

Perspective Wall / Document Lens

Perspective

Context gradually disappears

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

• combination of perspective

Calendar

• Leung

Why not magnifying glass?

• Hides local context

F+C vs. O+D• - distortion

• + smooth transition

• + more screen space efficient

• +easier layout

• - no flat overview, turn offf focus

• - eye swapping

• + higher zoom factor, higher scale

•+ really high scale with intermediates

•+ implementation (no math)

Next Week

• Tues: Visual Overview Strategies• Stasko, “Information Mural”

» ben, ahmed

• Rayson, “Aggregate Towers”» anil, supriya

• Thurs: Multiple View Strategies• Chi, “Visualization Spreadsheet”

» mudita, abhi

• North, “Snap-Together Visualization”» varun, kumar

Assignment

• Homework 2 due today