Database Reference
In-Depth Information
Table 11.2
Database Model.
Table
Description
Data Provided by AIS
Position reports of each ship with additional dynamic information.
MMSI
(numeric),
Time
(timestamp),
Heading
(numeric),
Speed
(numeric),
COG
(numeric),
ROT
(numeric),
Coordinates
(geom-
etry),
Status
(text)
AISPositions
Static information about ships.
MMSI
,
OMI_Number
(numeric),
Name
(text),
Callsign
(text),
Type
(text),
Length
(numeric),
Width
(numeric)
AISShips
AISTrips
Trajectory-based information.
MMSI
,
Draught
(numeric),
Danger
(Boolean),
Destination
(text),
ETA
(timestamp),
ReportedTime
(timestamp)
Derived Data Added to the Model
Trajectories
Trajectories extracted from raw data.
MMSI
,
BeginningTime
(timestamp),
EndTime
(timestamp),
Shape
(geometry)
Zones
Zones of interest (ZOI).
ZID
(numeric),
Name
(text),
Shape
(geometry)
Itineraries
Itineraries between ZOI.
IID
(numeric),
StartZoneID
(numeric),
EndZoneID
(numeric)
stored in a new table,
Zones
. The zones of interest can also be manually
defined by an operator according to various criteria such as regulations (waiting
areas, traffic channels, restricted areas), geography (obstacles, isthmuses, straits,
inlets), and economy (shops, loading sites, ports, fishing areas). These zones of
interest, represented as spatial zones, can be connected together to define a
zone graph
in order to analyze ships' mobility and describe their itineraries
(Table
Itineraries
).
For richer analysis, taking geographic information into account might also be
of interest. The database could therefore include a large set of tables obtained
from official S-57 vector charts that contain different kind of objects useful for
spatial analysis:
Points of interest: buoys, shipwrecks, containers at sea, etc.
Lines of interest: coastlines, path, channels, crossing lines, etc.
Zones of interest: oil spills, ports, restricted areas, PSSA, etc.
The zone graph of the Bay of Brest is illustrated in Figure
11.3
b. The numer-
ous dots shown in Figure
11.3
a represent positions of ships. An itinerary
I
is
