Fig. 5: Shipping behaviors extracted from historical trajectories.

a Clustering results of the shipping behaviors, where the first row shows the clusters of ships departing from Singapore, and the second row shows the clusters of ships departing from Rotterdam; b clustering comparison between different methods, where HDBSCAN, DBSCAN and DBTCAN stands for “Hierarchical Density-Based Spatial Clustering of Applications with Noise”, “Density-Based Spatial Clustering of Applications with Noise”, and “Density-Based Trajectory Clustering of Applications with Noise”, respectively.