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AISanalyze: an R-package to correct, interpolate, and extract AIS data |
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08 January 2024 |
paper.bib |
AISanalyze is an R-package developed to specifically correct GPS errors in AIS data, linearly interpolate the vessel positions at the desired times, and extract the locations and information of vessels around desired locations, at desired times. The advantage of this package is that the computation time is considerably reduced to perform these operations, enabling results to be obtained in few minutes to few hours depending on the size of AIS data and the number of points to extract. Furthermore, this package identifies the vessels from the base stations and aircrafts in the AIS data, based on the distance and speed travelled, allowing to filter only the first if desired. It extracts information on vessel length and type as well, by excluding errors on vessel length and type originally present in the AIS data. First, an all-in-one function was constructed to analyze, correct, and extract AIS data around desired locations, therefore:
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calculating the distance, time and speed travelled by each vessel;
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identifying base stations and aircrafts in the AIS;
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correcting GPS errors and GPS delays;
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interpolating the vessel positions at the customized times;
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extracting the vessel positions and their information around the desired locations, at the desired times.
However, each function is available individually as well. Second, a further function allows to linearly interpolate all AIS data at the desired temporal resolution, regardless of the location. Finally, a last function extracts the length and type of vessel per MMSI (Maritime Mobile Service Identity), removing the errors present in the AIS data. This information can later be added to the interpolated/extracted AIS data.
Human activities and their impacts on the ocean and their ecosystem components continue to increase (Halpern et al., 2008, 2015), and with them the maritime traffic. AIS (Automatic Identification System) and VMS data (Vessel Monitoring System) are the only sources of global data on vessel positions in real time to date. Studies on the impacts of maritime traffic are therefore heavily dependent on these data: however, numerous errors are found, due to GPS errors, GPS delays, and errors of receptions. This leads to vessel tracks with erroneous positions, speeds, and information (e.g., wrong vessel length and type). Furthermore, the huge size of the AIS data makes any overview complex and highly time-consuming. These two points greatly limit the research possibilities related to vessel tracks and densities including a wider context. Easy-to-use and fast calculation algorithms are required to fill these gaps and allow the community to use AIS data to carry out these researches. AISanalyze opens up a wide range of research possibilities, from studying the effects and distribution of maritime traffic to improving the treatment and shortcomings of AIS data.
We acknowledge contributions from Daniel Alexander Schwarzkopf, Volker Matthias, Tobias Schaffeld, and Dominik Nachtsheim. We would like to thank the German Federal Maritime and Hydrographic Agency (BSH) for providing the AIS data that enabled us to build, check and use this package. This work was conducted in the framework of the CoastalFutures project, funded by the German Federal Ministry of Education and Research (BMBF) under grant number 03F0911H. The responsibility for the content of this publication lies with the authors.
Halpern, B. S., Frazier, M., Potapenko, J., Casey, K. S., Koenig, K., Longo, C., Lowndes, J. S., Rockwood, R. C., Selig, E. R., Selkoe, K. A., & Walbridge, S. (2015). Spatial and temporal changes in cumulative human impacts on the world’s ocean. Nature Communications, 6, 7615. https://doi.org/10.1038/ncomms8615.
Halpern, B. S., Walbridge, S., Selkoe, K. a, Kappel, C. V, Micheli, F., D’Agrosa, C., Bruno, J. F., Casey, K. S., Ebert, C., Fox, H. E., Fujita, R., Heinemann, D., Lenihan, H. S., Madin, E. M. P., Perry, M. T., Selig, E. R., Spalding, M., Steneck, R., & Watson, R. (2008). A Global Map of Human Impact on Marine Ecosystems. Science, 319(5865), 948–952. https://doi.org/10.1126/science.1149345