Post on 28-Mar-2015
ENV 2006 7.1
Envisioning Information
Lecture 7 – Interaction
Ken Brodliekwb@comp.leeds.ac.uk
ENV 2006 7.2
Interaction
• Major difference between paper and computer-based visualization is ability to interact with picture and alter the presentation of the data
• Nice simple example is ‘Dancing with Histograms’– Dix and Ellis
http://www.comp.lancs.ac.uk/computing/users/dixa/papers/simple98/
• This lecture looks at two concepts:– Focus and context
– Brushing
ENV 2006 7.3
Focus and Context
• A recurring problem in Information Visualization is lack of screen real estate
• Challenge has been addressed in some innovative ways• Want to achieve:
– Focus: to see detail of immediate interest– Context: to see the overall picture
• Want to do this interactively…• Six approaches:
– Distortion– Rapid zooming– Elision– Multiple windows– Use 3D (more space)– Use animation (more time)
ENV 2006 7.4
Distortion: Bifocal Display
• As name suggests, distortion achieves aim by magnifying focus area and demagnifying surrounding context
• Probably the first suggestion was the bifocal display of Spence and Apperley (1982)
– Play Spence bifocal_lens movie (http://www.iis.ee.ic.ac.uk/~r.spence/videos.htm)
ENV 2006 7.5
Bifocal Display
• Implemented as an image browser that scales different areas of image in different ways
– Chris North, Univ of Maryland
Available at:http://people.cs.vt.edu/~north/infoviz/
ENV 2006 7.6
Bifocal Display
• A possible application is in map reading
• This London underground application was developed by Marcelo Cohen in Leeds
• Zoom / pan
• Focus /context
ENV 2006 7.7
What is the Bifocal Display Doing?
• Transforming the information space to the display space
– Visual transfer functions
Informationspace
DisplaySpace Normal
display
Informationspace
DisplaySpace
Bifocaldisplay
context
focus
ENV 2006 7.8
Developing the Idea
• Card, Robinson and McKinlay developed the idea into the ‘Perspective Wall’
ENV 2006 7.9
The Perspective Wall
2D layout wrappedaround a 3D structure
Space utilisation:-detail on centrepanel 3x size ofequivalent flat wall fitting field ofview
ENV 2006 7.10
Perspective Wall
• Advantages:– User can adjust ratio of
detail to context– Smooth animation helps
user perceive object constancy
– Relationship between detail and context is consistent: objects bend around the corner
ENV 2006 7.11
Perspective Wall
• In terms of transfer function, the situation is closer to the early Spence movie
– Perspective gives smoother transition from focus to context
Informationspace
DisplaySpace
PerspectiveWall
context
focus
ENV 2006 7.12
FishEye Menus
• Here is the same idea applied to menus– Ben Bederson, University of Maryland
• See also:– http://www.samuelwan.com/downloads/com.samuelwan.eidt/
fisheyemenu/FisheyeMenuDemo.html
ENV 2006 7.13
Comparison of Menu Styles
• Research pages at University of Maryland include a nice applet that allows you to compare different menu styles
– Arrow bar– Scroll Bar– Hierarchical– FishEye
• Screenshots on next slide created from:
– http://www.cs.umd.edu/ hcil/fisheyemenu/ fisheyemenu-demo.shtml
ENV 2006 7.14
Menus
arrow scrollhierarchical
fisheye
ENV 2006 7.15
Question
• What are the disadvantages of the magnifying glass paradigm for providing focus and context?
ENV 2006 7.16
Table Lens
• This is a focus and context idea specifically aimed at tables
• Try applet at:http://www.inxight.com/products/sdks/tl/
ENV 2006 7.17
Table Lens
ENV 2006 7.18
Rapid Zooming Techniques
• Idea is to allow rapid zooming between focus and context– Zoom in to focus, then out to context
• Recent idea is SDAZ – Speed Dependent Automatic Zooming– Linked to scroll bar
– Moving scroll bar fast will zoom out
– Slowing scroll bar will zoom in again
– See: http://www.cosc.canterbury.ac.nz/andrew.cockburn/liter.html
ENV 2006 7.19
Rapid Zooming Interfaces
• There is often a blurred distinction between zooming interfaces and distortion techniques
• Look at:http://www.cs.umd.edu/hcil/piccolo/index.shtml
New buzzword: ZUIs
ENV 2006 7.20
Elision Techniques
• Hide parts of a structure until they are needed• Widely used in graph drawing software for very large graphs• Have you seen this in xmdvtool?
ENV 2006 7.21
Multiple Views
• Multiple views can also be used to provide focus and context
• Powerpoint uses this to good effect!
ENV 2006 7.22
Move into 3D: Cone Trees
• Using a third dimension allows us to prioritise the focus (foreground) without losing the context (background)
• For large tree structures it is impossible to find sufficient screen space
• Cone trees in 3D provide a solution
• Here is a movie
http://research.compaq.com/SRC/3Danimate/conetree.html
ENV 2006 7.23
Adding a time dimension: RSVP
• We can gain more space by adding time!
• Recent Spence work addresses problem of browsing information spaces– Rapid Serial Visual Processing
– To gain a quick view of what is available
– Distinction between browsing and searching– Here is the movie (http://www.iis.ee.ic.ac.uk/~r.spence/videos.htm)
ENV 2006 7.24
Browsing the Web
• Spence has also turned his attention to browsing the web – On mobile devices!– Here is the movie (http://www.iis.ee.ic.ac.uk/~r.spence/videos.htm)
ENV 2006 7.25
Linking: Brushing
• Brushing has become a fundamental concept in visualizing information
– Already encountered in xmdvtool
ENV 2006 7.26
Linking: Coordinated Views
• Selection from one view can be linked to a corresponding selection in another view
– Coordinated multiple views
ENV 2006 7.27
Linking: Multiple Views
• Many of the concepts we have talked about are brought together in the Snap-Together system of Shneiderman and North
• How many visualizations can you recognise here?
http://www.cs.umd.edu/hcil/snap/
ENV 2006 7.28
Snap Together for Directories
ENV 2006 7.29
Linking: Spence Attribute Explorer
• Spence has also developed a tool called Attribute Explorer– Compare it with xmdvtool
– Look for brushing concept– Here is the movie (http://www.iis.ee.ic.ac.uk/~r.spence/videos.htm)