Quality Evaluation and Feature Analysis of Commercial Vessel Movement Data

Vessel positioning and the observation of detailed movements can be performed in real time using an automatic identification system (AIS). In recent years, the development of services providing AIS data collected by satellites and land-based facilities has been significant. This study aims to evaluate the quality of vessel-movement data provided by data-service companies and to elucidate global and time-series data characteristics. Specifically, we analyze the characteristics and quality of vessel-movement data, focusing on the acquisition status of AIS data and port-of-call data, the accuracy of draught data within AIS data, and the presence of surplus data in port-of-call data, by comparing them with data owned by shipping companies. The evaluation of AIS data indicated an increase in data-acquisition rates in recent years, reaching nearly 90% worldwide. The acquisition of quantified AIS data varied depending on the sea region. Port-of-call data acquisition exhibited high accuracy for several data sources. Additionally, the missing port-of-call data rate differed depending on the calling type and data source. Moreover, the unobserved port-of-call data rate differed considerably among the different data sources. Consequently, our findings confirmed that the characteristics and quality of the data varied depending on the specific data source.