Do we need/want an AIS filter?

[rgleason]

I have made the following changes to the AIS page. AIS | Official OpenCPN Homepage
Note: The main Options > Ships > AIS Targets page also needs to be updated.


AIS Operating Controls
The Menubar-AIS and Toolbar-AIS provide useful operating controls of key AIS parameters which may need to be adjusted during use.

[Image of Menubar-AIS]

Menubar > AIS dropdown
(To turn on the Menubar use Options > User Interface > Show Menubar)

• Show AIS Targets
• Hide Moored AIS Targets
• Attenuate Less critical AIS Targets
• Show AIS Target Tracks
• Show CPA Alert Dialogs
• Sound CPA Alarms

These controls appear to work together and in sync, as expected:
Menubar AIS: Show AIS Targets = Options > Ships > AIS Targets > Display: Show AIS - NOTE not available. See below.
Menubar AIS: Hide Moored AIS Targets = Options > Ships > AIS Targets > Display: Suppress Anchored/Moored Targets...
Menubar AIS: Attenuate Less.. [Exception, see below]
Menubar AIS: Show AIS Target tracks = Options > Ships > AIS Targets > Display: Show Target Tracks Length (min)
Menubar AIS: Show CPA Alerts = Options > Ships > AIS Targets > CPA/TCPA Alerts: Show CPA/TCPA Alert Dialogs
Menubar AIS: Sound CPA Alarms = Options > Ships > AIS Targets > CPA/TCPA Alerts: Play sound to CPA/TCPA Alerts...

Options > Ships > AIS Targets > Display: "Allow attenuation of less critical targets..." must be checked for
Menubar AIS: "Attenuate Less Critical AIS Targets" to be un-greyed and available.
Also when unavailable, the Toolbar AIS Icon click rotation drops the selection for "Attenuate all AIS targets".

[Image of Toolbar-AIS]
Toolbar AIS Icon Message (Clickable Rotation to change settings. Read the pause message.)

• Attenuate Less Critical AIS Targets
• Hide AIS Targets
• Show all AIS Targets
• Attenuate all AIS Targets (dropped in rotation if unchecked under Options > Ships > AIS Targets)

Further down...
After Suppress Anchored/Moored

Allow attenuation of less critical targets if more than ...targets [number]
If checked AND selected under Menubar-AIS or Toolbar-AIS then at least [number] of targets will be displayed normally. If unchecked then all AIS targets are displayed normally and this option is greyed out and unavailable.
[Image of Attenuated AIS]
Attenuation of Less Critical Targets will declutter the display without removing AIS targets from the display, by reducing the size of less critical targets. Less critical targets are determined with a weighted rules filter. The important targets remain unchanged, including display of the ships name. Less critical targets are reduced in size and do not display ship name, to reduce clutter on the chart.

[rgleason]

These are the two improvements in operating controls that I believe should be made for consistency in the interface.

Menubar AIS: Uncheck Show AIS and an X does not appear in the Toobar AIS Icon, as it should.

Menubar AIS: Uncheck Show AIS and under Options > Ships > AIS Targets > Display: there is no checkbox for Show all AIS targets that can be unchecked, similar to most other controls.

[rgleason]

The first one is fixed.
The second one is added to Tracker
FS#1934 : AIS Control Interface Consistency - Show AIS Targets

[rgleason]

With Dirk's proximity filter "Attenuate less critical targets" in place now.

It might be useful to review older but interesting discussion and information about AIS Filters
http://www.setsail.com/class-b-ais-f...-myth-is-real/
Panbo: The Marine Electronics Hub: Class B AIS filtering, the word from Dr. Norris
Panbo: The Marine Electronics Hub: Class B AIS filtering, the word from Dr. Norris
Panbo: The Marine Electronics Hub: AIS SOLAS-style, Class B is NOT ignorable!

and a consideration not yet really resolved...
http://www.cruisersforum.com/forums/...ty-134157.html

[Gatorbait]

A filter would be useful that would stop OpenCPN from calculating CPA, TCPA, etc. for ships not visible in the current chart view or based on distance. We are currently in Japan with often 50+ ships in range of up to 40 miles or so. Having many AIS targets causes OpenCPN to have a lag of 5 seconds or more in responding to mouse or keyboard input. Have tried closing the comms port connected to the AIS feed to determine if the delay was caused by dealing with the comms port or OpenCPN calculations. Lost targets is set to 10 minutes. The delay continues after the comms port is closed and goes away at the end of 10 minutes when the targets have cleared. Zooming the chart to only showing a couple of ships doesn't fix the delay.

Perhaps it is my old hardware and software: Dell laptop D620, Intel Duo CPU T7300 2 GHz, 4 GB ram, 64 bit Win 7, No OpenGL. OpenCPN v 4.6.1

No collisions yet. Love OpenCPN!

[bcn]

How does this setting look like in your case?

[Gatorbait]

Here are my current settings with the options ticked. Can try some other values as you suggest tomorrow as we will be underway.

Here are the current settings. Tried to insert a pic but didn't know how to do it as the request was for a URL when clicked on insert image.

No (T)CPA Alerts if target range is greater than (NMi) 3.0
Warn if CPA less than (NMi) 2.0
...and TCPA is less than (min) 20

Thanks for your help.

[bcn]

When opening the reply window you can use the paperclip from the tools on top to attach a file.
It will open a second window in order to select the file you want to upload.
The upload button gets sometimes hidden under the right edge. Just use the slider or widen the upload window.
(and don't forget to close the upload window - if not it will live there until you close the session)

[transmitterdan]

Originally Posted by Gatorbait

Here are my current settings with the options ticked. Can try some other values as you suggest tomorrow as we will be underway.

Here are the current settings. Tried to insert a pic but didn't know how to do it as the request was for a URL when clicked on insert image.

No (T)CPA Alerts if target range is greater than (NMi) 3.0
Warn if CPA less than (NMi) 2.0
...and TCPA is less than (min) 20

Thanks for your help.

If you have the Voyage Data Recorder plugin it would be nice to have a long file that contains such AIS target data. Then we could run it through OpenCPN and see where the calculations need to be sped up. I have a VDR file that has probably 100 AIS targets all on the screen at the same time and I don't see any slow down because of that. So another VDR file that causes a slow down would be nice.

If you have a github account and the git tool on your computer you could upload it to a forked VDRplayer repository.

First, fork this repository using the github.com web site. Log on to github. If you don't have a github username you can create an account for free. It only takes a few minutes. Then go to this address:

https://github.com/transmitterdan/VDRplayer

In the upper right you will see a button labeled "Fork". Click it and follow the instructions.

You can get the git tool for your computer here:

https://git-scm.com/downloads

Assuming your github username is gatorbait you would then do this at a windows command prompt:

git clone https://github.com/gatorbait/VDRplayer.git
cd VDRplayer
git checkout -b VDRproblem

--------Then copy the VDR recorder file to the VDRplayer folder like this using the actual name when you saved it (not mynewVDRfile.txt):

copy mynewVDRfile.txt .
git add mynewVDRfile.txt
git commit --all --message="Add problem file"
git push --set-upstream origin VDRproblem

Post a message here telling that you have done this and I will pull the file and see if I can find what is causing the slowdown.

It may seem like this is complex but it isn't that hard. I guess it would take only a few minutes if you have a decent internet connection. The long part is recording the data into a VDR text file.

PS: For Linux the commands are the same except change the command "copy" to "cp".

[Gatorbait]

Okay, I will install the VDR plugin and get the log to github. I am no longer convinced it is simply the number of AIS targets causing the slowdown. It may have something to do with forwarding NMEA messages on the serial port. Am trying to filter different NMEA sentences to see if I can isolate the issue.

Thanks so much for your detailed and helpful response!