Multilevel Compound Tree – Construction Visualization and Interaction

Several hierarchical clustering techniques have been proposed to visualize large graphs, but fewer solutions suggest a focus based approach. We propose a multilevel clustering technique that produces in linear time a contextual clustered view depending on a user-focus. We get a tree of clusters where each cluster – called

meta-silhouette

– is itself hierarchically clustered into an inclusion tree of

silhouettes

. Resulting

Multilevel Silhouette Tree

(

MuSi-Tree

) has a specific structure called

multilevel compound tree

. This work builds upon previous work on a

compound tree

structure called

MO-Tree

. The work presented in this paper is a major improvement over previous work by (1) defining

multilevel compound tree

as a more generic structure, (2) proposing original space-filling visualization techniques to display it, (3) defining relevant interaction model based on both focus changes and graph filtering techniques and (4) reporting from case studies in various fields: co-citation graphs, related-document graphs and social graphs.