The visualisation tool allow to individuate  particles that are
initially sedded in a particular area by moving the cursor on the map
of the Mediterranean. In particular it is possible both to give a particular weight
to the cursor (option point in the plot plane and area size) and directly select the
area by choosing the coordinates in the left panel (Lat/Lon option in the plot plane)

Then  from the netcdf file it is extracted a new one containing only
those particles originating in the selected area.

The smaller netcdf file can be downloaded and/or plotted. Ferret is used
as "plotting engine", but any other graphical package capable to read
netcdf files could easily be used (Grads is certenly one of them).

The particles starting in the selected area are extracted from the entire file  clicking the button

'Extract trajectories'

It is possible then or to download the relative netcdf file, or visualise the Centre of mass trajectory,
the  particles trajectories and the mean root square displacement