Area notice
11.1 This message provides dynamic information concerning a specified geographic area, polyline or positions. It should be only used to convey pertinent time-critical navigation safetyinformation to mariners or authorities, and not as a means to convey information already provided by current official nautical charts or publications.
11.2 This message can also be used to convey advisory lines or tracks. However, the Route Information message should be used for recommended or directed routes.
11.3 The information is time-dependent (i.e. has start date and time and duration).
11.4 In order to allow advance notice, this message should be transmitted prior to the start date and time specified for the area. It should not be transmitted more than one day in advance.
11.5 This message should not be transmitted beyond the end date and time, except for a cancellation message. A cancellation message can be transmitted before the designated end date and time using the same Message Linkage ID with an Area Type of 126 (cancellation), a Duration = 0, and start date and time fields all set to not available.
11.6 ECDIS/ECS software should automatically remove the area notice from the display after the end date and time specified or after receiving a cancellation message.
11.7 Up to 5-slots message can be created, however messages with more than 3 slots should be avoided. Messages with more than 3 slots are less likely to be received due to radiofrequency noise or packet collision.
11.8 Waypoints can be specified using the polyline/waypoint sub-area. In case more precision is to be required then multiple circle/point sub-areas can be defined (e.g., one for each waypoint).
11.9 When waypoints are specified using polyline or circle/point sub-areas, they should be numbered and used in the order that they appear in the message.
11.10 Polyline/polygon sub-areas must follow immediately after a point sub-area (Area Shape 0) in the same Area Notice message. The point defines the start of the line segments. If more than 5 points were required for a polyline/polygon, then additional polyline/polygon sub-areas could be used. However, they must follow immediately after the first polyline/polygon sub-area.
11.11 The Message Linkage ID can be used to link additional text (e.g., a separate text message). However, both the Area Notice and additional Text Description message should be sent by the same source MMSI.
11.12 The total area defined by one Area Notice (one Message Linkage ID) is the union of all of the sub-areas contained in the message.
11.13 If the same Message Linkage ID is retransmitted with different sub-areas and/or times, then the ECDIS/ECS should replace the old Area with the new.
11.14 The Message Linkage ID must be unique across all binary messages to which it applies. In this way, the Message Linkage ID and Source MMSI are connected to the same text message.