Description: This density heat map of vessel traffic patterns in the Mediterannean Sea was constructed using a line density calculation of vessel tracklines from July-August 2014 Satellite-based Automatic Information System (AIS) data points. Pixel size is 100 meters, and the search radius is 800 meters. It is important to understand that while Satellite AIS data can be used to construct general vessel traffic patterns, erroneous data points and interpolation errors exist. The pixel values are not directly representing the exact number of transits through a spatial area, but rather a relative measure of trackline density.