We consider orthogonal upward drawings of directed acyclic graphs (DAGs) with nodes of uniform width but node-specific height. One way to draw such graphs is to use a layering technique as provided by the Sugiyama framework . However, to avoid drawbacks of the Sugiyama framework we use the layer-free upward crossing minimization algorithm suggested by Chimani et al. and integrate it into the topology-shape-metric (TSM) framework introduced by Tamassia . This in combination with an algorithm by Biedl and Kant  lets us generate column-based layouts, i.e., layouts where the plane is divided into uniform-width columns and every node is assigned to a column.
We show that our column-based approach allows to generate visually appealing, compact layouts with few edge crossing and at most four bends per edge. Furthermore, the resulting layouts exhibit a high degree of symmetry and implicitly support edge bundling. We justify our approach by an experimental evaluation based on real-world examples.
- Directed Acyclic Graph
- Outgoing Edge
- Incoming Edge
- Edge Segment
- Edge Crossing
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