A route planning method for small ships in coastal areas based on quadtree

Abstract

Route planning for large commercial ships generally revolves around economic factors, such as fuel consumption and travel distance, which are often influenced by maritime weather conditions. In contrast, small ships navigating coastal areas, such as yachts, prioritize safety and navigational convenience. Although extensive research has been conducted on route planning for commercial ships, more studies focusing on small ships are required. This study introduces a novel route planning method for coastal areas tailored to small ships. The proposed method begins by generating quadtree charts derived from an S-57 chart. Considering the lower computational performance typically observed for small ships, a quadtree chart offers a more efficient solution than a traditional regular grid. This structure allows for high-resolution representation only where necessary, considering water depth and coastal obstacles to ensure safe navigation. The route planning process comprises two layers: high-level and low-level. The high-level layer uses lower-resolution charts to outline a general route between the departure and arrival points and to identify key entrances along the way. The low-level layer, which employs higher-resolution charts, generates a detailed route from the departure point to the entrance and from the entrance to the arrival point. The final step involves smoothing to ensure a seamless and navigationally efficient route. Adopting a hierarchical approach can significantly enhance the efficiency of route planning by utilizing a multi-level structure, thereby reducing the time required for route planning. This methodology enables more effective responses in continuous maritime environments, ensuring high efficiency even during real-time route updates and modifications. The proposed method was applied to the coastal areas of the Republic of Korea to assess its effectiveness. In this study, the proposed method was compared with conventional chart generation methods. The results demonstrate that the method provides suitable and safe route planning for small ships, offering a reliable approach for coastal area navigation.