Nodes groups visualization

17 February 2009

Design ~

Loic Fricoteaux, student in Computer Science worked on a Gephi research project about visual representation of nodes groups. Next big move of Gephi will be supporting clustering and hierarchy navigation. Thus this project helps to keep network readibility within cluster exploration. We expect presence of this functionality for the first 0.7 release, later this year.

Implicit surface system on a sample graph
Implicit surface system on a sample graph

The purpose of this module is to enable users to highlight nodes groups in a graph, providing a better visibility for them. For instance, it can be useful to reveal/highlight patterns or just to highlight meaningful nodes aggregates in a network.

To visually represent nodes groups, each node of a group has a circular (by default) influence area which decreases as long as the distance from the associated node increases. A thresholding of the summation of all these influence areas defines a surface (not necessary connected) enclosing every nodes in a smoothness manner. The final rendering can be hugely parameterized to match user preferences (size of influence areas, color, antialiasing, …).

Computing surface

In order to allow a real-time rendering for many nodes groups in big dynamic graphs, an optimized algorithm has been specifically developed to fill the corresponding enclosing surfaces while keeping a handsome rendering.

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