Authors:
Sebastian Hahn
;
Jonas Trümper
;
Dominik Moritz
and
Jürgen Döllner
Affiliation:
Hasso-Plattner-Institute, Germany
Keyword(s):
Hierarchical Visualization, Voronoi Treemaps, Stable Layout, Changing Hierarchies.
Related
Ontology
Subjects/Areas/Topics:
Abstract Data Visualization
;
Computer Vision, Visualization and Computer Graphics
;
General Data Visualization
;
Graph Visualization
;
Information and Scientific Visualization
;
Software Visualization
;
Visual Data Analysis and Knowledge Discovery
Abstract:
Space-restricted techniques for visualizing hierarchies generally achieve high scalability and readability (e.g.,
tree maps, bundle views, sunburst). However, the visualization layout directly depends on the hierarchy, that
is, small changes to the hierarchy can cause wide-ranging changes to the layout. For this reason, it is difficult
to use these techniques to compare similar variants of a hierarchy because users are confronted with layouts
that do not expose the expected similarity. Voronoi treemaps appear to be promising candidates to overcome
this limitation. However, existing Voronoi treemap algorithms do not provide deterministic layouts or assume a
fixed hierarchy. In this paper we present an extended layout algorithm for Voronoi treemaps that provides a high
degree of layout similiarity for varying hierarchies, such as software-system hierarchies. The implementation
uses a deterministic initial-distribution approach that reduces the variation in node positioning even if chan
ges
in the underlying hierarchy data occur. Compared to existing layout algorithms, our algorithm achieves lower
error rates with respect to node areas in the case of weighted Voronoi diagrams, which we show in a comparative
study.
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