IALA

Area notice

Introduction/Additional information:

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.

Area notice – (broadcast)

Parameter No of bits Description
Standard Message Header Message ID 6 Identifier for Message 8; always 8.
Repeat Indicator 2 Used by the repeater to indicate how many times a message has been repeated (see ITU-R M.1371-3, Annex 2, § 4.6.1).

0 – 3

0 = default

3 = do not repeat anymore

Source MMSI 30 MMSI number of source station.
Spare 2 Not used.  Set to zero.
Binary Data Designated Area Code 10 DAC = 001
Function Identifier 6 FI = 22
Application Data Message Linkage ID 10 A source specific running number, unique across all binary messages equipped with Message Linkage ID. Used to link additional information to the message by a Text Description message. The Message Linkage ID and the first six digits of the source MMSI uniquely identify the sent message.

1 – 1,023

0 = not available = default

Notice Description 7 Notice description as defined in Table 11.11
Set to 0 – 127 according to description. If = 127 there must be associated text (see Table 11.10)
Start date and time of Area UTC Month 4 Start UTC month of the Area notice.

1 – 12

0 = not available = default

13 – 15 (reserved for future use)

UTC Day 5 Start UTC day of the Area notice.

1 – 31

0 = not available = default

UTC Hour 5 Start UTC hour of the Area notice.

0 – 23

24 = not available = default

25-31 (reserved for future use)

UTC Minute 6 Start UTC minute of the Area notice.

0 – 59

60 = not available = default

61-63 (reserved for future use)

Duration 18 Minutes until the end of Area notice, measured from start date and time of Area Notice.
0 = cancel Area Notice262,143 = undefined = default
Maximum duration is 262,142 minutes (182.04 days)
Sub-areas max 870 From 1 to 10 sub-areas, each structured as in Tables 11.4 – 11.9. A short text description may be associated with the areas using Sub-area 5: Associated text (see Table 11.10). Total number of sub-areas is determined by the length of the message. Each sub-area is a fixed 87 bits.
Total max 981 Occupies 2-5 slots (see Table 11.3)

Table 11.3

Number of slots

Number of sub-areas  transmitted 1 2 3 4 5 6 7 8 9 10
Number of bits used for a broadcast message 198 285 372 459 546 633 720 807 894 981
Number of slots used for a broadcast message 2 2 3 3 3 4 4 4 5 5
Number of bits used for an addresses message 230 317 404 491 578 665 752 839 926 1013
Number of slots used for an addressed message 2 2 3 3 3 4 4 5 5 5

Table 11.4

Sub-area table

Number Area Shape Table for Definition
0 circle or point 11.5
1 rectangle 11.6
2 sector 11.7
3 polyline 11.8
4 polygon 11.9
5 associated text  11.10
6 – 7 reserved

Table 11.5

Circle or point

Parameter No of bits Description
Area Shape 3 Defines the shape of the area.
Set 0 for Circle.
Scale Factor 2 Scale factor. This is a multiplier for the dimensions of the shape.
1 (default), 10, 100, & 1,000 (scale factor = 10n where n=decimal value of scale factor).
Longitude 25 Longitude of the centre in 1/1,000 min, ±180 degrees as per 2’s complement (East = positive, West = negative).

181 = not available = default

Latitude 24 Latitude of the centre in 1/1,000 min, ±90 degrees as per 2’s complement (North = positive, South = negative).

91 degrees = not available = default

Precision 3 Precision of data in latitude and longitude parameters.

Data to be truncated to the number of decimal places specified in this parameter.

0 – 4

4 = default

Radius 12 Defines the size of the circular area. This is the radius of the circle in metre steps.
0 = point (default)1 – 4,095 metres

This is multiplied by the scale factor to give a maximum size of 4,095,000 metres (4,095 km).

Spare 18 Not used. Set to zero.

Table 11.6

Rectangle

Parameter No of bits Description
Area Shape 3 Defines the shape of the area.
Set 1 for Rectangle.
Scale Factor 2 Scale factor. This is a multiplier for the dimensions of the shape.
1 (default), 10, 100, & 1,000 (scale factor = 10n where n=decimal value of scale factor).
Longitude 25 Longitude of the SW corner in 1/1,000 min, ±180 degrees as per 2’s complement (East = positive, West = negative).

181 = not available = default

Latitude 24 Latitude of the SW corner in 1/1,000 min, ±90 degrees as per 2’s complement (North = positive, South = negative).

91 degrees = not available = default

Precision 3 Precision of data in latitude and longitude parameters.

Data to be truncated to the number of decimal places specified in this parameter.

0 – 4

4 = default

E dimension 8 Box dimension East from the corner point, in metre steps. This is multiplied by the scale factor to give a maximum dimension of 255,000 metres (255 km).

0 = line North-South (default)

1 – 255 * scale factor metres.

N dimension 8 Box dimension North from the corner point, in metre steps. This is multiplied by the scale factor to give a maximum dimension of 255,000 m (255 km).

0 = line East-West (default)

1 – 255 * 10^scalefactor metres

Orientation 9 Rotation of area, in degree steps. Area is rotated clockwise this number of degrees about the position above.
0 = no rotation = default1-359 = rotation in degrees

360-511 (reserved for future use)

Spare 5 Not used Set to zero.

Figure 11-1

Description of the process required to define a “rectangle” area

rect_area

Table 11.7

Sector

Parameter No of bits Description
Area Notice: Sub-area Area Shape 3 Defines the shape of the area.

Set 2 for Sector.

Scale Factor 2 Scale factor. This is a multiplier for the dimensions of the shape.
1 (default), 10, 100, & 1,000 (scale factor = 10n where n=decimal value of scale factor)
Longitude 25 Longitude of the centre in 1/1,000 min, ±180 degrees as per 2’s complement (East = positive, West = negative).

181 = not available = default

Latitude 24 Latitude of the centre in 1/1,000 min, ±90 degrees as per 2’s complement (North = positive, South = negative).

91 degrees = not available = default

Precision 3 Precision of data in latitude and longitude parameters.

Data to be truncated to the number of decimal places specified in this parameter.

0 – 4

4 = default

Radius 12 Defines the size of the sector, in metre steps. This is multiplied by the scale factor to give a maximum size of 4,095,000 m (4095 km).

0 = point = default

1 – 4,095 metres

Left Boundary 9 Orientation of the left boundary edge of the sector, in degree steps measured clockwise from true North about the centre point.

0 = no rotation= default

1 – 359 = rotation in degrees

360-511 (reserved for future use)

Right Boundary 9 Orientation of the right boundary edge of the sector, in degree steps measured clockwise from true North about the centre point. The total sector area is the area measured from the left boundary clockwise to the right boundary.

0 = no rotation= default

1 – 359 = rotation in degrees

360-511 (reserved for future use)

Spare 0 Not used. Set to zero.

Figure 11-2

Sector Area

sect_area

a)        Centre point

b)        Sector radius

c)        Sector bearings from centre point, left boundary

d)       Sector bearings from centre point, right boundary

Table 11.8
Waypoint/polyline points
Parameter No of bits Description
Area Notice: Sub-area Area Shape 3 Defines the shape of the area.

Set to 3 for Polyline (open area or line). The initial point (point 0) is defined by an Area Shape = 0 (circle)

Scale Factor 2 Scale factor. This is a multiplier for the dimensions of the shape.
1 (default), 10, 100, & 1,000 (scale factor = 10n where n=decimal value of scale factor)
Point 1 Angle 10 True bearing, in half-degree steps, from Point 0 to Point 1 or from the last Point in a Polyline directly preceding this Polyline.
Degrees bearing = decimal value (0-719)*.5720 = not available = default

721 – 1,023 (reserved for future use)

Point 1 Distance 10 Distance, in metre steps, from Point 0 to Point 1 or from the last Point in a Polyline directly preceding this Polyline. This number (1 – 1,023) is multiplied by the scale factor to give a maximum of 1,023,000 metres (1,023 km).

0 = default (no point).

Point 2 Angle 10 True bearing, in half-degree steps, from Point 1 to Point 2.
Degrees bearing = decimal value (0 – 719)*.5720 = not available (no point) = default

721 – 1,023 (reserved for future use)

Point 2 Distance 10 Distance, in metre steps, from Point 1 to Point 2. This number (1 – 1,023) is multiplied by the scale factor to give a maximum of 1,023,000 metres (1,023 km).

0 = default (no point).

Point 3 Angle 10 True bearing, in half-degree steps, from Point 2 to Point 3.
Degrees bearing = decimal value (0-719)*.5720 = not available (no point) = default

721 – 1,023 (reserved for future use)

Point 3 Distance 10 Distance, in metre steps, from Point 2 to Point 3. This number (1 – 1,023) is multiplied by the scale factor to give a maximum of 1,023,000 metres (1,023km).

0 = default (no point).

Point 4 Angle 10 True bearing, in half-degree steps, from Point 3 to Point 4.
Degrees bearing = decimal value (0 – 719)*.5720 = not available (no point) = default

721 – 1,023 (reserved for future use)

Point 4 Distance 10 Distance, in metre steps, from Point 3 to Point 4. This number (1 – 1,023) is multiplied by the scale factor to give a maximum of 1,023,000 metres (1,023 km).

0 = default (no point).

Spare 2 Not used.  Set to zero.

Figure 11-3

Graphic description of a waypoint/polyline, showing angle and distance between points

(if one side of a polyline is to be a boundary (e.g., edge of ice area), this is defined by the left side of the line in order of sequence from the initial sub-area point (Point 0))

graph_desc

Figure 11-4

Graphic depiction of:

1) ice boundary between sea ice and open water, and

2) recommended route through the sea ice area

ice

Figure 11-5

Graphic depiction of a storm front message

storm_area

Table 11.9
Polygon
Parameter No of bits Description
Area Notice: Sub-area Area Shape 3 Defines the shape of the area.

Set to 4 for Polygon (closed area).

The polygon shape is closed by connecting the last defined point back to the initial point (Point 0). To be preceded by an Area Shape = 0 (circle)

Scale Factor 2 This is a multiplier for the dimensions of the shape.
1 (default), 10, 100, & 1,000 (scale factor = 10n where n=decimal value of scale factor)
Point 1 Angle 10 True bearing in half-degree steps, from Point 0 to Point 1 or from the last Point in a Polygon directly preceding this Polygon.
Degrees bearing = decimal value (0 – 719)*.5720 = not available = default

721 – 1,023 (not for use)

Point 1 Distance 10 Distance in metre steps, from Point 0 to Point 1 or from the last Point in a Polygon directly preceding this Polygon. This number (1 – 1,023) is multiplied by the scale factor to give a maximum of 1,023,000 metres (1,023 km).
Point 2 Angle 10 True bearing in half-degree steps, from Point 1 to Point 2.
Degrees bearing = decimal value (0 – 719)*.5720 = not available (no point) = default

721 – 1,023 (not for use)

Point 2 Distance 10 Distance in metre steps, from Point 1 to Point 2. This number (1 – 1,023) is multiplied by the scale factor to give a maximum of 1,023,000 metres (1,023 km).

0 = default (no point).

Point 3 Angle 10 True bearing in half-degree steps, from Point 2 to Point 3.
Degrees bearing = decimal value (0-719)*.5720 = not available (no point) = default

721 – 1023 (reserved for future use)

Point 3 Distance 10 Distance in metre steps, from Point 2 to Point 3. This number (1 – 1,023) is combined with the scale factor to give a maximum of 1,023,000 metres (1,023 km).

0 = default (no point).

Point 4 Angle 10 True bearing in half-degree steps, from Point 3 to Point 4.
Degrees bearing = decimal value (0-719)*.5720 = not available (no point) = default

721 – 1,023 (not for use)

Point 4 Distance 10 Distance in metre steps, from Point 3 to Point 4. This number (1 – 1,023) is multiplied by the scale factor to give a maximum of 1,023,000 metres (1,023 km).

0 = default (no point).

Spare 2 Not used. Set to zero.

Table 11.10

Associated text

Parameter No of bits Description
Area Notice Sub-area Area Shape 3 Defines the shape of the area.

Set 5 for Associated text.

This text is associated with the area defined in this binary message. Multiple Associated text sub-areas are glued together in the order they appear in the message.

Text 84 14 characters 6-bits ASCII characters, as defined in ITU-R M. 1371-3, Table 44. If less than 14 characters are required, then the remainder of the field should be filled with “@” characters.
Spare 0 Not used. Set to zero.

Table 11.11

Notice Description

 

Caution Area: Marine mammals habitat 32 Restricted Area: Fishing prohibited 64 Distress Area: Vessel disabled and adrift 96 Chart Feature: Sunken vessel
1 Caution Area: Marine mammals in area -reduce speed 33 Restricted Area: No anchoring. 65 Distress Area: Vessel sinking 97 Chart Feature: Submerged object
2 Caution Area: Marine mammals in area – stay clear 34 Restricted Area: Entry approval required prior to transit 66 Distress Area: Vessel abandoning ship 98 Chart Feature: Semi-submerged object
3 Caution Area: Marine mammals in area – report sightings 35 Restricted Area: Entry prohibited 67 Distress Area: Vessel requests medical assistance 99 Chart Feature: Shoal area
4 Caution Area: Protected habitat – reduce speed 36 Restricted Area: Active military OPAREA 68 Distress Area: Vessel flooding 100 Chart Feature: Shoal area due north
5 Caution Area: Protected habitat – stay clear 37 Restricted Area: Firing – danger area. 69 Distress Area: Vessel fire/explosion 101 Chart Feature: Shoal area due east
6 Caution Area: Protected habitat – no fishing or anchoring 38  Restricted Area: Drifting Mines 70 Distress Area: Vessel grounding 102 Chart Feature: Shoal area due south
7  Caution Area: Derelicts (drifting objects) 39  (reserved for future use) 71 Distress Area: Vessel collision 103 Chart Feature: Shoal area due west
8 Caution Area: Traffic congestion 40 Anchorage Area: Anchorage open 72 Distress Area: Vessel listing/capsizing 104 Chart Feature: Channel obstruction
9 Caution Area: Marine event 41 Anchorage Area: Anchorage closed 73 Distress Area: Vessel under assault 105 Chart Feature: Reduced vertical clearance
10 Caution Area: Divers down 42 Anchorage Area: Anchoring prohibited 74 Distress Area: Person overboard 106 Chart Feature: Bridge closed
11 Caution Area: Swim area 43 Anchorage Area: Deep draft anchorage 75 Distress Area: SAR area 107 Chart Feature: Bridge partially open
12 Caution Area: Dredge operations 44 Anchorage Area: Shallow draft anchorage 76 Distress Area: Pollution response area 108 Chart Feature: Bridge fully open
13 Caution Area: Survey operations 45 Anchorage Area: Vessel transfer operations 77 (reserved for future use) 109 (reserved for future use)
14 Caution Area: Underwater operation 46 (reserved for future use) 78 (reserved for future use) 110 (reserved for future use)
15 Caution Area: Seaplane operations 47 (reserved for future use) 79 (reserved for future use) 111 (reserved for future use)
16 Caution Area: Fishery – nets in water 48 (reserved for future use) 80 Instruction: Contact VTS at this point/juncture 112 Report from ship: Icing info
17 Caution Area: Cluster of fishing vessels 49 (reserved for future use) 81 Instruction: Contact Port Administration at this point/juncture 113 (reserved for future use)
18 Caution Area: Fairway closed 50 (reserved for future use) 82 Instruction: Do not proceed beyond this point/juncture 114 Report from ship: Miscellaneous information – define in Asociated text field
19 Caution Area: Harbour closed 51 (reserved for future use) 83 Instruction: Await instructions prior to proceeding beyond this point/juncture 115 (reserved for future use)
20 Caution Area: Risk (define in Associated text field) 52 (reserved for future use) 84 Proceed to this location – await instructions 116 (reserved for future use)
21 Caution Area: Underwater vehicle operation 53 (reserved for future use) 85 Clearance granted – proceed to berth 117 (reserved for future use)
22  (reserved for future use) 54 (reserved for future use) 86 (reserved for future use) 118  (reserved for future use)
23 Environmental Caution Area: Storm front (line squall) 55 (reserved for future use) 87 (reserved for future use) 119 (reserved for future use)
24 Environmental Caution Area: Hazardous sea ice 56 Security Alert – Level 1 88 Information: Pilot boarding position 120 Route: Recommended route
25 Environmental Caution Area: Storm warning (storm cell or line of storms) 57 Security Alert – Level 2 89 Information: Icebreaker waiting area 121 Route:

Alternative route

26 Environmental Caution Area: High wind 58 Security Alert – Level 3 90 Information: Places of refuge 122 Route:

Recommended route through ice

27 Environmental Caution Area: High waves 59 (reserved for future use) 91 Information: Position of icebreakers 123 (reserved for future use)
28 Environmental  Caution Area: Restricted visibility (fog, rain, etc) 60 (reserved for future use) 92 Information: Location of response units 124 (reserved for future use)
29 Environmental  Caution Area: Strong currents 61 (reserved for future use) 93 VTS active target 125 Other – Define in associated text field
30 Environmental  Caution Area: Heavy icing 62 (reserved for future use) 94 Rouge or suspicious vessel 126 Cancellation – cancel area as identified by Message Linkage ID
31  (reserved for future use) 63  (reserved for future use) 95  Vessel requesting non-distress assistance 127 Undefined (default)