Identify and visualize Dutch inland waterways vessel movement anomalies during low water levels
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This MSc thesis aims to develop a workflow analyzing inland vessel traffic anomalies during low water levels by using historical automated identification system (AIS) data. Low water level impacts inland waterway transports because cargo ships must carry less weight in order to stay safe and afloat. The consequences are the same amount of freight needs more trips to be transported comparing to normal water level times, and more trips lead to busier waterways and higher freight rates. Many inland transportation reports and news articles have discussed the impacts of low water levels on inland shipping, but not many studies have used AIS data and water level data to analyze the relationship. Thus, this research tries to fill in this gap in two aspects: validate the market observations and detect vessel interaction anomalies. AIS is a system that broadcasts vessel status and information to other vessels in the same area, so vessels can know each other’s whereabouts and act accordingly. The information contained in AIS data are categorized as dynamic and static information, the first changes depending on the position and movement of the vessel, while the latter is about vessel identity and voyage information such as vessel IDs, destination, vessel types, and vessel size. The spatial and temporal information in AIS data can provide researchers an opportunity to look into this topic from a different perspective. Therefore, the research question is: to what extent can historic AIS data contribute to the analysis of the impacts brought by low water level in inland waterways? The research was divided into two phases. First, four statements were summarized based on news articles and market reports, and a workflow was developed to validate those statements with AIS data analysis. Second, the vessel interaction anomalies were narrowed down to starboard side encounter events, which are allowed under certain conditions in the study area. Ship encounters were detected by the distance to the other ship, then the encounter events were classified by which side of the ship they met. The study results show that AIS data can be used to identify how busy the waterway was by extracting and counting the number of trips. However, analysis that uses draught value as the data source is not recommended since the draught values in AIS data are not reliable. The analysis on the speed and water levels shows no correlation between these two elements, thus the statement is not true. On the other hand, the results of vessel size changes indicate that there are no significant patterns regarding vessel size and water levels, which might be because of a wrong study area. Lastly, the analysis results of ship-encounter anomalies present that starboard side encounters are related to how busy is the waterway.