Algorithm 1: Data preprocessing

Input: Original dataset $X_{T_j}$, minimum voyage time interval threshold $\epsilon$. Output: Trajectories $T_{s_i}.$

1: Connect to the database.

2: Get $V_i$ where $i$ in Len$\left(O\right)$ and $V_i$.//$\Delta t$ is the total time interval of voyage $i$.

3: if $R_i.mmsi$ = $R_{i-1}.mmsi \&\&R_i.sog<1kn \&\& {\delta }_t<1200s$ where ${\delta }_t$ = $R_i.t-R_{i-1}.t$//$R_i$ is the next state of $V_i$,$R_i.sog$ is the speed of the vessel, ${\delta }_t$ is the time interval between two-state.

4: then Optimization ($V_i$), $T_{s_i}\to V_i$.//Optimize ($·$) is the trajectory optimizing function. Return:$T_{s_i}$