browsing hierarchical data with multi-level dynamic queries and pruning

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Browsing Hierarchical Data with Multi-level Dynamic Queries and Pruning. By H. P. Kumar, C. Plaisant & B. Schneidernam Presented by: Dawit Yimam Seid. Tree Representations. Node-link visualization 2D (outline, tree diagrams) 3D (Cone Trees) Tree-map visualization (nested & non-nested) - PowerPoint PPT Presentation


  • Browsing Hierarchical Data withMulti-level Dynamic Queries and PruningBy H. P. Kumar, C. Plaisant & B. Schneidernam

    Presented by: Dawit Yimam Seid

  • Tree RepresentationsNode-link visualization2D (outline, tree diagrams)3D (Cone Trees)Tree-map visualization (nested & non-nested)Graph structures (hypertext, flow charts, etc.)

  • HDS/Tree BrowsingHierarchical browsinginteraction matches structureWhen do we do hierarchical browsing ?hierarchical decision making, iterative refinement/progressive querying of datasetse.g. sales & budget data, catalog of products, computer file systemsmost AND queries can be considered hierarchicale.g. SEX=male AND M_STATUS=single AND INCOME>=200,000

  • Tree Browsing - requirementsSomewhat contradictoryRetain context - not getting lost deep in the treevs.Dont display non-relevant information

    How to achieve both at the same time ?

  • PDQ Tree-Browsers ApproachEnable viewing tree at different levelsSelection (filtering) criteria at various levels in the treeattribute based specification of the foci of interestHide uninteresting nodes and branches rapidly

  • PDQ Tree-Browser TechniquesDynamic Queries & tight couplinglet users dynamically query nodes at each leveltightly couple query widgets to tree visualizationtightly couple the overview and detail viewsAutomatic Pruning(in addition to zooming and panning)automatically prune out uninteresting nodes/sub-trees to get more compact views

  • Dynamic Queries for Tree BrowsingApplying DQ to trees is challenging !Predefined relationships between data points (unlike the case of flat/independent data sets). A query at one node affects other nodesDynamic generation of widgets since nodes at different levels can have different attributes, andsince these nodes are dynamic

  • The PDQ Tree-Browser InterfaceData display - two resizable windowsOverview (left)Detail view (right)Dynamic Query PanelAttribute list (shows attributes of the current lowest level)Widgets panel - widgets created by usersrange-sliders (for numeric)menu (for text)

  • The PDQ Tree-Browser Interface FeedbackIndicatorWidgetsPanelAttributesListOverviewField-of-viewDetailedviewLevel namebuttonLevelincrement/decrement

  • Query & ManipulationQuery using WidgetsQueries AND-ed together and matching nodes colored yellow in real timeManipulating a widget at an internal node level makes that node the current lowest levelTree structure changed throughlevel buttonswidgets+ or - buttonspan detail view dragging the field-of-viewTwo types of coupling !

  • PruningDone when depth of the tree is increased.Children of non-matching nodes are prunedOrange shows non-pruned nodes

  • Example ApplicationThe UniversityFinder

  • PDQ Tree-Browser LimitationsMax depth of 5only up to 3 attributes to query; queries only AND-edscrolling the overview needed when tree is largeClicking nodes in detail view do not open their sub-trees

  • Issues/AlternativesPruning Vs. graying out ?To change tree structure as widgets are created or not ?How to handle large trees ?Maintain overview to detail view coupling ?Intermediate views, let user restrict before displayHow to generalize the PDQ Tree-Browser to other tree representations (e.g. treemap)where to place widgets ? How to prune ?How to add OR and NOT queries ?

  • Usability Testing8 subjects (2 pilot, 6 test)7 tasks (feature based & task-based)Results (on a scale of 1-9)8.7 - pruning (+Hide Grey Leaves) is useful8.2 - dynamic query is useful4.8 - easiness of range-slider manipulationSome users did not like the dynamic widget creation !

  • Controlled ExperimentGoal - compare Full-tree, Partially-pruned tree and Fully-pruned tree25 subjects; 7 tasksResultsTask completion time1. Fully-pruned 2. Partially-pruned 3. Full-treeSubjective satisfaction rate1. Partially-pruned 2. Fully-pruned 3. Full-treeNo clear cut finding on graying Vs. hiding pruned nodes


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