Using the Gestalt Principle of Closure to Alleviate the Edge Crossing Problem in Graph Drawings

Abstract

Graphs, generally used as data structures in computer science applications, have steadily shown a growth in mapping various types of relationships, from maps to computer networks to social networks. As graph layouts and visualizations have been at the forefront of graph drawing research for decades, it consequently led to aesthetic heuristics that not only generated better visualizations and aesthetically appealing graphs but also improved readability and understanding of the graphs. A variety of approaches examines aesthetics of nodes, edges, or graph layout, and related readability metrics. In this paper we focus on the edge crossing problem and propose a solution that incorporates Gestalt principles to improve graph aesthetics and readability. We introduce the concept of breaks in edges at edge crossings. A break is a gap in an edge drawing occurring in the vicinity of an edge crossing. At every edge crossing, one of the incident edges is broken, which will prevent any unintentional Gestalts that occur at edge crossings that reduce the readability of a graph drawing. We present our preliminary results and user studies that show that this technique could play a role in improving graph readability.