An improved approach for assessing marine traffic complexity based on Voronoi diagram and complex network

The shipping industry is constantly expanding, and maritime traffic is increasing in numerous navigable waters. For maritime traffic safety, improving Situation Awareness (SA) is critical. However, the majority of relevant research placed a greater emphasis on the risk of a collision between two ships, but failed to capture the complexity of the global traffic situation. In this paper, a framework for evaluating marine traffic complexity is developed. With the combination of the Voronoi diagram and complex network, an improved Marine Traffic Complex Network (MTSCN) is coming into being. The geometric features of Voronoi diagram are used to divide the water area into multiple cells, setting safe distances is avoided by treating ships as neighbors and other ships. The impact of neighbors on the situation awareness and the impact of other ships on the collision risk of own ship are considered. This method can more truly demonstrate the traffic complexity in the water area. Simulations are introduced to investigate the validity of the proposed method with two ships crossing situation, three ships crossing situation and four ships crossing situation. The proposed method is further demonstrated using actual AIS data in the Yangtze River, and the correlation between complexity and other indicators has been analyzed. The result shows that the improved MTSCN may give an intuitive and accessible measure to capture the essence of maritime traffic, which will be helpful in understanding, monitoring, and controlling maritime traffic safety in the future. Additionally, the complexity based on MTSCN could enhance the SA of VTSOs by supporting decision-making.