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Traffic Density Mapping Service (TDMS)


The use of Traffic Density Maps (TDM) is a simple and effective way to show vessel movement patterns. The TDM contribute to a better understanding of maritime traffic and help to answer important questions, such as where the main shipping lanes are, by whom are they used and which ship types are navigating per each route. The TDM are produced by compiling ship’s positioning data and can highlight the presence of congested areas. The TDM can be used for different purposes including risk assessments and traffic planning.

Traffic Density Mapping Service

Following the HLSG 2 (Brussels, 20 June 2017), EMSA developed the Traffic Density Mapping (TDM) service using AIS data (both terrestrial and satellite) based on the methodology agreed at the HLSG 3 (Brussels, 28 February 2018).

There is no international standard definition or method to create TDM. Most methodologies are based on grid-based approaches, whereby the area to be monitored is divided into cells to create a spatial grid. The methodology approved by the HLSG for traffic density plotting is based on calculating of the number of routes recorded for a specific ship within a specific cell of the grid during a specified time period.

For the purposes of the TDM service, EMSA developed a tool that automatically generates vessel density maps using ship positioning data collected from Terrestrial AIS and Satellite AIS data sources, as well as the existing maritime infrastructure and application environment of the SafeSeaNet Ecosystem Graphical Interface (SEG).

Currently, the TDM service is provided for five ship type ranges (“Cargo”, “Tanker”, “Passenger”, “Fishing”, “All Other” and “All traffic”) and predefined areas (North Sea/Atlantic, Atlantic, Baltic Sea, Black Sea and Mediterranean Sea, as well as the area of “All Europe”). The service allows users to visualise the overall ship traffic density within the selected area during predefined periods (e.g. one month, quarterly or annually) by using data of the previous month as well as historical data.

An example of a TDM from the Baltic Sea area is presented below.

The service is developed gradually, considering the possibilities offered by the technology and the user requirements. Based on the feedback received form the users, the service may be enhanced to offer more functionalities.

Baltic Sea All data Dec2018Baltic Sea – All ship types (December 2018)

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