Animated Visualization of Multiple Intersecting Hierarchies

George Robertson, Kim Cameron, Mary Czerwinski, Daniel Robbins
2002 Information Visualization  
We describe a new information structure composed of multiple intersecting hierarchies, which we call a Polyarchy. Visualizing polyarchies enables use of novel views for discovery of relationships which are very difficult using existing hierarchy visualization tools. This paper will describe the visualization design and system architecture challenges as well as our current solutions. Visual Pivot is a novel web-based polyarchy visualization technique, supported by a "polyarchy server"
more » ... with a Mid-Tier Cache architecture. A series of five user studies guided iterative design of Visual Pivot. Finally, we discuss the effectiveness of animation in Visual Pivot. While Figure 1 only shows one hierarchy view (Management), users need to see other hierarchy views, and we need a way to transition between them. We use a new visualization technique called Visual Pivot, with two hierarchies simultaneously displayed around a designated entity called the pivot point (the first entity in a query set). This is a visual analog to a database pivot, where a view of one dimension is replaced with a view of another dimension. An animation pivots from one hierarchy view to another, giving the user a chance to see the relationship between the hierarchies in the context of the selected pivot point, if necessary. Perhaps more importantly, the pivot animation helps the user maintain context during complex transitions. While we have described these polyarchy problems in terms of databases about people and resources, the problems occur with any collection of databases that have entities appearing in more than one of the databases. For example, a But polyarchies are multiple intersecting hierarchies, sharing at least one node rather than sharing subtrees. Hence, MultiTrees are a subset of polyarchies. The added complexity requires a new approach as described in this paper. POLYARCHY VISUALIZATION TECHNIQUE: VISUAL PIVOT The goals of polyarchy visualization are: (1) to show the user how selected entities relate to each other in a hierarchy; (2) to make it easy for a user to move from one hierarchy view to another without losing context; and (3) to help the user see how various hierarchies relate to each other in the context of selected entities. We envision this latter goal to be of increasing importance as metadirectories become more common. We focus on selected entities and their paths to the root of each hierarchy, instead of general overviews of extremely large hierarchies. Traditional tree views show expanded subtrees (e.g., all siblings of any given node), making it difficult to scale to large
doi:10.1057/palgrave.ivs.9500002 fatcat:bbmyzs7f6rd4zialroqi7bs3gi