This dataset contains information on vessel movements in the North Sea and Dutch Inland Waterways for the months January, April, July, and October in 2019. It provides a heatmap representation of vessel traffic density during these specific months, which can be useful for various maritime and environmental analyses. 1.File Formats The dataset is provided in the following file formats: NetCDF : The primary data files are available in netcdf format. For each grid cell the variables sog (Speed Over Ground) and count (Number of AIS messages) are available GeoTIFF (Georeferenced Tagged Image File Format): Heatmap images are provided in GeoTIFF format, suitable for geographic visualization. The dataset is split into tiles. Each tile conforms to the OSM tiling naming scheme. 2. Variables The dataset includes the following key variables: Speed Over Ground (SOG) : The average vessel's speed over the ground for all the messages. Count : The number of AIS messages received in this location 3. Data Collection Method The AIS data used in this dataset was collected from AIS transponders on vessels operating in the North Sea and Dutch Inland Waterways. These transponders transmit information such as vessel position, speed, and identification. The dataset aggregates this information to create heatmap images for analysis. We did this on all the messages. Some ships emit more messages than others. Ships emitmessages at higher frequency when sailing than when stationary. 4. Source of Original Data The original AIS data used to create this dataset was sourced from the AIS archive from Rijkswaterstaat. This dataset was analysed for the purpose of a storymap .