Prof. Dr. Jürgen Döllner


Tel.: +49-(0)331 5509-3921
Fax: +49-(0)331 5509-172
Room: H-2.22
Email: sebastian.hahn(at)hpi.de

Research Interests

  • Visual Software Analytics
  • Metaphor-based Visualization
  • Layout Stability
  • Evaluation of Visualization Techniques





Visualization of Varying Hierarchies by Stable Layout of Voronoi Treemaps

Hahn, Sebastian; Trümper, Jonas; Moritz, Dominik; Döllner, Jürgen in Proceedings of the 5th International Conference on Information Visualization Theory and Applications (IVAPP 2014) Seite 50-58 . SCITEPRESS – Science and Technology Publications , 2014 .

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 changes 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.
Weitere Informationen
Tags Changing_Hierarchies Hierarchical_Visualization Stable_Layout Voronoi_Treemaps cgs


WiSe 2016/17

  • Lecture 3D Computergraphics I (tutor)


  • Seminar Methods and Techniques of Software Visualization (tutor)
  • Lecture 3D Computergraphics II (tutor)


  • Seminar Systems Engineering for Software Analytics (tutor)


  • Seminar Visual Software Analytics (tutor)
  • Lecture Einführung in die Programmiertechnik II (tutor)


  • Seminar Visualization for Interactive Software Analytics (tutor)
  • Bachelor's project Software Analytics and Visualization (co-supervisor)

SoSe 2014

  • Lecture 3D Computergraphics I (tutor)

WiSe 2013/14

  • Seminar Software Analytics (tutor)
  • Seminar Game Programming (tutor)

SoSe 2013

  • Lecture Geovisualization (tutor)
  • Seminar Softwarevisualisierungsverfahren (tutor)

WiSe 2012/13

  • Bachelor's project A Visualization Tool for Software Evolution (co-supervisor)

SoSe 2012

  • Lecture Visualization (tutor)
  • Seminar Softwareanalyseverfahren (tutor)

Master's Theses

  • ThreadCity: Combined Visualization of Structure and Activity of Multi-threaded Software Systems - Nikolai Wuttke (finished

Further Activities

  • Participant of ETH Winter School on Eye Tracking  (January 2016)
  • Teaching-Team Member OpenHPI Course "Automated Visual Software Analytics" (March 2015)
  • SoftVis project in cooperation with the SAP Innovation Center, Potsdam (April 2012 - March 2016)