Cushion Treemaps and Botanical Visualization

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Cushion Treemaps and Botanical Visualization

• Yimeng Dou
• 05-16-2002
• ydou_at_ics.uci.edu

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Overview

• Trees and Cushion Treemaps
• SequoiaView Software
• Botanical Trees

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Cushion Treemaps

• Provide shading as a strong extra cue to
  emphasize hierarchical structure.
• Especially good for answering global questions
  like Why is my disk full?

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Example Trees
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root
Example Trees
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A disk with color scheme option off.
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Same disk with color scheme on. Treemap
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Treemap

• Efficient use of display space
• Constructed via recursive subdivision of the
  initial rectangle
• Size of each rectangle is proportional to the
  size of the node
• Subdivision is alternated per level first
  horizontally, next vertically

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Treemap

• Most useful when the feature we want to display
  is size
• Not very good for visualizing structure of the
  tree (Worst case is balanced tree)
• What happens if its a perfectly balanced tree of
  items all the same size?

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Example 3600 Employees
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Nested Treemap

• Use slightly smaller rectangles. Siblings are
  enclosed by a margin.
• Require viewers effort when tree is deeply
  nested.
• Coloring wont help much. It does not provide a
  natural hierarchical structure, and we want to
  use color to show other attributes.

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Nested Tree-Map
Non-nested Tree-Map
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The Idea Behind Cushion Treemaps

• Human visual system interprets variations in
  shade as illuminated surfaces. So shape can be
  constructed to encode tree structure.

Add a bump to each of the two subdivisions, and
repeat recursively.
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The Parabolic Surfice
Z is height of such a surface.
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InteractionSequoiaView

• SequoiaView is an interactive system for the
  analysis and visualization of large tree
  structures.
• Cushion tree can be easily constructed and If
  there is any change, Sequoia can easily refresh
  the tree.
• User can define size range, color scheme, can
  zoom in on sub-trees, zoon out again, and select
  preferred color scheme and filters.

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lt- Sound Garden
Cure
Cure--Disintegration
Sound Garden Studio Albums Only
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Cushion Treemaps (Conclusion)

• Efficient, quick generation of treemap image
• Effective (shading provide a strong cue for
  identifying substructures)
• Compact, no scrolling neccessary
• Easy to implement (with the shown algorithm)
• Easy to control with intuitive parameters
• Wide applicability

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Botanical Visualization of Huge HierarchiesIdea

• People can easily see branches, leaves and their
  arrangement in a botanical tree.
• We can use the idea of botanical modeling for
  Information Visualization, and map folders to
  branches and files to leaves.
• The model usedstrand model (dates back to
  Leonardo Da Vinci) by Holton.

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Strand Model

• Leaves are connected to root via a strand
• Area of branch is proportional to number of
  leaves.

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Node and Link Diagram and Its Corresponding
Botanical Tree
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Problems

• Continuing branches representing a directory
  cant be easily followed at the branching point.
• Those directories with many sub-directories lead
  to thin and long branches.
• Leaves tend to clutter.

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An Example Of A Messy Tree
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Continuation Without Extrusion

• Smooth continuing branches (by adding a smooth
  transition between two cylinders).
• It makes clear what the status of each branch is.
• We can also use different color as an extra cue.

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Contraction Long Branches

• Conditionally remove the stem in the subbranch of
  the continuing branch. It replaces the binary
  tree with a general tree.

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Files As Fruits

• To prevent cluttering of leaves, we can use an
  icon to represent a list of files and their
  sizes. It can be modeled as a fruit consisting of
  a sphere with spots for each file.(Phi-ball)
• Area of slices on the sphere is proportional to
  the size of the corresponding files.
• When there is only one file, using cone instead
  of planar disks pasted on the sphere.

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Phi-balls
Cones length c equals to the square root of the
ratio of the file size and the total size of the
file list.
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Final Results
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Complete Hard Disk
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A Unix Home Directory
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Conclusions

• Cone covered phi-ball is good for visualizing a
  list of items, also useful for other applications
• Branches and cones hardly ever collide with no
  special prevention
• Efficient use of space by mathematical,
  algorithmic and physically based methods.

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END

• Special thanks to Daniel Loewus-Deitch for
  providing graphs of his music library.