Layer Assignment Problem with Alignment Constraints of Source and Sink Vertices for Visualizing Evaluation Structures

Abstract

An evaluation structure is a hierarchical structure of human cognition extracted from interviews based on the evaluation grid method. An evaluation structure can be defined as a directed acyclic graph (DAG) and be visualized by the Sugiyama framework that is a popular graph drawing method. In this paper, we discuss a layer assignment method that is a part of Sugiyama framework for interactive visualization of evaluation structures. We propose a novel heuristic method to approximately solve the layer assignment problem in polynomial time. We compare the performance of the proposed method with an exact method and an existing approximate solution method. It is demonstrated that the proposed method produces readable layout in a short time.