Can We Interpret the Depth?: Evaluating Variation in Stereoscopic Depth for Encoding Aspects of Non-Spatial Data

Abstract

Rendering a 2D node-link representation on a stereoscopic platform supports the idea of having a natural focus+context interaction. In this case, stereoscopic depth can be used to encode the different levels of detail in compound graphs, especially for highlighting the structural relations. We propose an approach that provides a novel interactive operation for expanding or contracting nodes in compound graphs to align these nodes in the 3D space with minimum occlusion, such that the children levels are rendered in a plane closer to the viewer than the parent node. Different visual cues can also be used together to encode other data aspects, e.g., color for encoding node status or shape for encoding node type. The focus of this paper is on a controlled user study that we conducted with 30 participants to evaluate the approach using different configurations. The aim of the study was to understand the viewers' ability of detecting the variation in stereoscopic depth as well as the influence of graph size and the transparency on this ability in terms of accuracy and efficiency. Further, we were interested to measure the participants' acceptance towards our approach of using the stereoscopic depth as a cue for compound graphs. The study results show that stereoscopic depth can be used to encode data aspects of compound graphs under certain circumstances.