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4.2.2.1 Drafting voyage plan 
DFD 1.1 shows that the data flow “Correction information" represented in DFD 1 consists of three com 
ponents: 
track-related correction information 
route-related correction information 
correction information for the speed/time profile 
The data flow “Voyage plan data” shown in DFD 1 has been broken down in DFD 1.1 into the compo 
nents route data, track data, set speeds and passage and arrival times. It should be borne in mind that 
the data flow “Set speeds” may contain speeds through the water or over ground. The set speed used 
as a basis in the system at any given time during the voyage must correspond to the sensor technology 
available. The basic assumption when considering voyage plan data is that the voyage plan may adopt 
two “statuses”: “route" or “track”. These differ in terms of their reference to the surrounding environ 
ment. A track has a unique local reference (particularly with regard to the geographical, meteorological 
and hydrographic conditions considered) while a route has more of a global character. Thus a track is 
automatically “more detailed” than a route. Since only the track takes into account local details (eg wa 
terway, traffic separation regions), only these may form the basis for automatic track control. 
DFD 1.1: Task “Drafting voyage plan’