Cushion Treemaps and Botanical Visualization Yimeng Dou 05 16 2002 ydou ics uci edu Overview Trees and Cushion Treemaps SequoiaView Software Botanical Trees 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 Example Trees Example Trees root A disk with color scheme option off Same disk with color scheme on Treemap 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 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 it s a perfectly balanced tree of items all the same size Example 3600 Employees Nested Treemap Use slightly smaller rectangles Siblings are enclosed by a margin Require viewer s effort when tree is deeply nested Coloring won t help much It does not provide a natural hierarchical structure and we want to use color to show other attributes Nested Tree Map Non nested Tree Map 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 The Parabolic Surfice Z is height of such a surface Interaction SequoiaView 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 Sound Garden Cure Cure Disintegration Sound Garden Studio Albums Only 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 Botanical Visualization of Huge Hierarchies Idea 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 used strand model dates back to Leonardo Da Vinci by Holton Strand Model Leaves are connected to root via a strand Area of branch is proportional to number of leaves Node and Link Diagram and Its Corresponding Botanical Tree Problems Continuing branches representing a directory can t be easily followed at the branching point Those directories with many subdirectories lead to thin and long branches Leaves tend to clutter An Example Of A Messy Tree 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 Contraction Long Branches Conditionally remove the stem in the subbranch of the continuing branch It replaces the binary tree with a general tree 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 Phi balls Cone s length c equals to the square root of the ratio of the file size and the total size of the file list Final Results Complete Hard Disk A Unix Home Directory 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 END Special thanks to Daniel LoewusDeitch for providing graphs of his music library