EU Joint Research Centre: Figure 2

A zoom of the area (in Figure 1). Vessel positions from the ship transponder (VMS positions as filled squares and triangles) are plotted along the positions detected in the SAR image (VDS positions as open green circles). Triangular VMS positions are interpolated from the discrete VMS positions records in the postgresql/postgis taken before and after the image acquisition. Interpolation is triggered as a PL/PgSQL function inside the data base. Square VMS positions are within 2 minutes of the SAR image acquisition time.

VDS circles which are not matched by a nearby VMS square or triangle are an indication for the presence of unregulated fishing vessels.