A Coloring Algorithm for Disambiguating Graph and Map Drawings

TL;DR

This paper introduces a novel coloring algorithm that enhances the clarity of non-planar graph and map drawings by automatically assigning distinctive colors to disambiguate overlapping edges, improving visual comprehension.

Contribution

The paper presents a new branch-and-bound algorithm for near-optimal color assignment in graph drawings, addressing edge crossing ambiguities with a novel space decomposition approach.

Findings

Effective in clarifying real-world graph drawings

Reduces visual confusion caused by edge crossings

Demonstrates improved readability in complex maps

Abstract

Drawings of non-planar graphs always result in edge crossings. When there are many edges crossing at small angles, it is often difficult to follow these edges, because of the multiple visual paths resulted from the crossings that slow down eye movements. In this paper we propose an algorithm that disambiguates the edges with automatic selection of distinctive colors. Our proposed algorithm computes a near optimal color assignment of a dual collision graph, using a novel branch-and-bound procedure applied to a space decomposition of the color gamut. We give examples demonstrating the effectiveness of this approach in clarifying drawings of real world graphs and maps.