the picture   Ordered Bundles

Edges in graph drawings show relations between graph nodes. When the number of edges becomes large very often edges on a drawing cross and overlap each other in a rather chaotic way. This makes the node relations difficult to analyze. Recently edge bundling techniques were developed where some edge segments running close are collapsed into thick bundles. These techniques were a step forward but it was still usually difficult to follow an edge in a bundled drawing because no care was taken about ordering edges inside of a bundle, or a bundle avoiding a node. We suggest a solution that creates edge bundles avoiding nodes and where still a single edge can be followed. We use the ink minimization to create bundles and the metro-line ordering approach to order the edges inside of the bundles.

Here are some images of drawings obtained with the new methods.

The map of airplane routes over US

 

Collaboration map or researches in Graph Drawing

 

Book graph

Comparison of the standard routing and the ordered bundles methods

The methods compliment each other. With the standard technique, the figure on the right, it is easier to answer the question "Do Wolff and Byrka have a paper together?".  With ordered bundles it is easier to identify an author with the largest number of co-authors.

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