ExpanD: a stereoscopic expanding technique for compound graphs

In this work, we present a new technique, called ExpanD, for expanding compound nodes in stereoscopic platforms. In this technique, stereoscopic depth is used to encode the structural relationships in compound graphs using the containment representation, while explicit edges are used to represent the adjacency relations between the graph nodes. Further, stereoscopic depth is used to show the parent-child relations in such a manner that the children level is rendered in a plane closer to the viewer than the parent node. The technique provides a novel interactive operation for expanding or contracting nodes in order to align graph nodes in the 3D space with minimum occlusion. Different visual cues are used together to encode other data aspects, e.g., color to encode node status, shape to encode node type, and stereoscopic depth to encode hierarchical relations between nodes.