Before going into very specialized AIS features, I would suggest making the AIS presentation S-52 Preslib compliant. This would help not only keeping it standardized, but also considerably reduce the clutter problem experienced with many AIS targets and discussed here AIS Class B targets
There are many additional improvements possible in AIS presentation without resorting to filtering targets out, but a good start is implementing S-52 compliance.
This is based on a post I made in the BR24 radar project
A problem with the AIS presentation in OpenCPN
is that it's not IMO S-52 Preslib compliant.
1. All AIS targets should be a hollow triangle, no fill colour is allowed.
2. Normal targets are always blue, regardless of Class A/B or type of ship.
3. Dangerous targets (if implemented) are red.
4. Sleeping targets (if implemented) are blue and smaller.
When scale allows, targets can be drawn to scale around the GPS
position, with or without the not-to scale symbol inside as well.
Using these S52 standard symbols there is rarely any problem with hiding information, neither chart-based nor radar-derived.
Targets based on radar
information are green, for example ARPA targets are green circles (since their orientation is not known). Most professional systems do target correlation between AIS and radar, and a target that has identity and heading from AIS, but position updates from radar, are green triangles in every ECDIS system I have seen.
I have attached a sample of a S52 compliant presentations. Also the own-ship presentation is S52-compliant, something I dearly miss in OpenCPN
. It's also allowed but not mandatory to draw own-ship to scale when possible in chart scale. I'm running parallel to Jutlandica on her starboard side. You can see both to-scale and standard AIS symbols. (BTW, also the waypoints and route
lines are S52 standard, they should be orange.)
Red (Dangerous) AIS target:
Transas Navi-Sailor ECDIS, AIS & ARPA target fusion (vector partial time marks are optional):