Modeling for survey priority and extended CATZOC classifications of Swedish territorial waters in the Baltic Sea

Abstract: Hydrographic measurements and producing of sea charts are a vital part of safe navigations for vessels and ships. A request by the SMA in Norrkoping was made to extend CATZOC classifications in Swedish territorial waters by creating a model which could predict how fast the bathymetry would change at different locations. Models and maps were made in ArcMap GIS which would predict bathymetric changes of the seafloor in the Baltic Sea. Factors in the models include seabed type, the slope of the seafloor, and maritime transportation corridors. Survey priority maps were also made and include apart from the above-mentioned factors, the age of the latest FSIS-44 approved survey of Swedish territorial waters. These models and maps could be used to see where areas would have a need to be reclassed from A1 classification to a lower classification, or the need for the area to be re-measured. The results show a promising start where correlations between changes of the bathymetry over the years and predicted changes by the model could be made in small areas. This work opens a new way to assess changes in the bathymetry of Swedish territorial waters without the need to re-measure surfaces and helps to know which areas would be prioritized to be re-measured.