Vessels / Meeting Points
Meeting Points (Only SEAiq Pilot)
When an AIS target is following the same route, it can be useful to estimate where they may meet along the route. This is called their Meeting Point.
If traveling opposite directions, the meeting point is where the two vessels pass each other. When the vessels are in the same direction the vessel behind is overtaking the vessel in front, the meeting point is the location where they are overtaken.
This feature is commonly used when navigating rivers and similar confined channels, where the vessels can be expected to follow the course of the river. SEAiq will estimate the time until they meet and the approximate point of meeting along the route. The meeting point is displayed as a magenta circle along with the name of the target.
The AIS tab has an option called Route Traffic for organizing targets on your current route along with their meeting points.
IMPORTANT: the meeting point estimate uses a number of assumptions, such as that the vessels are actually following the same route, they maintain current speed, etc. The estimate is only accurate to the degree that the assumptions hold. In the case of vessels with similar speeds overtaking each other, the estimate may have a significant amount of error.
The following conditions must be met for a meeting point to be displayed:
You can see the time to meeting by pulling up the AIS record. The current status is displayed under "Route Meeting Point." If there is no meeting point, the status given will help you understand why not. The possible status values for meeting point are:
- Own-Ship must be following a route.
- The target must be moving at least 1kn.
- Both vessels must be within a maximum distance from the route. The default maximum is 1nm, but this can be adjusted in the settings below.
- Each vessel must be within 25 degrees of the direction of the route segment it is on.
- To be displayed on the chart, the meeting point must be a minimum range from Own-Ship. This is done to avoid clutter. The default minimum range is 0.25NM.
- The meeting point must be somewhere along the route.
- Vessels meet in time
- Own-Ship overtakes Target in time
- Target overtakes Own-Ship in time
- Vessels moving apart
- Own-Ship pulling away from Target
- Target pulling away from Own-Ship
- Own-Ship/Target not on route
- Speed for Target below 1kn threshold
- No position for Target/Own-Ship
- No course for Target/Own-Ship
- No speed for Target/Own-Ship
- Vessels meet past end of route
- Show Meeting Points: (Only SEAiq Pilot) This enables display of Meeting Points for AIS targets.
- Show Lines for Meeting Points: (Only SEAiq Pilot) When enabled, lines are shown at meeting points perpendicular to the route.
- Distance Threshold: (Only SEAiq Pilot) This is the maximum distance Own-Ship or an AIS target may be from the current route and still be considered to be following the route. Further conditions for a vessel to be considered following a route are in the Meeting Point overview.
- Small Vessel Length: (Only SEAiq Pilot) AIS targets less than this length have meeting points shown with green Meeting Point symbols. This can be used to identify smaller vessels.
- Only Show Selected AIS Target: (Only SEAiq Pilot) When enabled, only show the meeting point for the currently selected AIS target.
- Minimum Range: (Only SEAiq Pilot) Only display the meeting points that are at least this far from Own-Ship. This can help in reducing clutter and distractions around Own-Ship. The default minimum range is 0.25NM
- Meeting Point Alarm: (Only SEAiq Pilot) Alarm fires when new vessels appear on your route with a meeting point.
- Passing Restriction Alarm: (Only SEAiq Pilot) Alarm when a meeting point is detected along active route segment where passing is restricted. This is only done for vessels larger than Small Vessel Length.
Cross-Route Meeting Points (Experimental)
- Enable Cross-Route: (Only SEAiq Pilot) When enabled, cross-route distances are displayed.
- Threshold Distance: (Only SEAiq Pilot) Distance used to consider when two vessels are approaching too close.