Feature Requests

[P_Dub]

Does anyone has current data and time of change, including dirctions of Torres Strait (Australia)? I would apprciate.
Thanks.

[Dsanduril]

Originally Posted by P_Dub

Does anyone has current data and time of change, including dirctions of Torres Strait (Australia)? I would apprciate.
Thanks.

Do you mean to use in OpenCPN (because this is an odd thread for a general question)? Or just in general?

You can get the most recent predictions here but you should be aware of the notes that accompany them:

Torres Strait (Hammond Rock) Queensland

From the tidal point of view, Torres Strait is probably the most complex area in the world. Its narrow and shallow channels connect two oceans with different mean sea levels caused by the general oceanic circulation patterns. This difference introduces a westward equalising current. In addition, tidal regimes on both sides of the Strait are completely different, with diurnal tides to the west and semi diurnal to the east.

The contrast in regimes is caused by the difference of semi diurnal components of tide at either entrance, the diurnal part being generally uniform in the area. At some phases of the moon it can be high water at one entrance when it is low water at the other. In consequence, marked differences between the levels at the entrances occur resulting in strong tidal streams. While the tides may have a large diurnal component (especially at the western entrance), the tidal streams are predominantly semi diurnal.

Throughout the Prince of Wales Channel and its approaches, from Twin Island in the east to a few miles west of Goods Island, the streams flow at the times predicted for Hammond Rock (see predictions on the following pages). The rates diminish as the channel becomes less restricted and at its western entrance are only about 30 percent of those predicted at Hammond Rock. At Booby Island the rates are comparatively weak and the streams are of different character.

Near Harvey Rock and Saddle Island the streams commence and reach their maximum rates about 30 minutes earlier than at Hammond Rock, but in these more open waters the rates are comparatively weak. In Endeavour Strait the streams commence and reach their maximum rates about 40 minutes later than at Hammond Rock and, except for the more restricted parts of the Strait, their rates do not exceed 30 percent of those at Hammond Rock.

It has to be remembered however, that tidal stream predictions for Hammond Rock do not include any non tidal flows, like the equalising current mentioned above or currents caused by meteorological influences. In addition, the El-Niño Southern Ocean Oscillation can cause a drop of sea level of about 0.5 metres on the eastern side of the Strait in a very short time. The resultant changes to the water levels in the Strait, and to the current and stream direction and rates are impossible to predict.

[P_Dub]

Thanks for the info. I take care.

[CapnRon47]

I have a Garmin Chartplotter at the helm which allows me to 'Mark' my current location with a waypoint. So for example, when sailing in a race I can sail past both ends of the start line and mark each end with a waypoint. MY QUESTION IS: is there a way to get those most recent waypoints from my Garmin (which talks on the NMEA0183 bus that OpenCPN is connected to) into OpenCPN and use their location to perform some subsequent calculation; like show the time from my 'new' current location back to the waypoints?

I think it would require something in OpenCPN or a plugin to constantly monitor waypoint updates in my Garmin.

thanks,
Ron

[RhythmDoctor]

Originally Posted by CapnRon47

I have a Garmin Chartplotter at the helm which allows me to 'Mark' my current location with a waypoint. So for example, when sailing in a race I can sail past both ends of the start line and mark each end with a waypoint. MY QUESTION IS: is there a way to get those most recent waypoints from my Garmin (which talks on the NMEA0183 bus that OpenCPN is connected to) into OpenCPN and use their location to perform some subsequent calculation; like show the time from my 'new' current location back to the waypoints?

I think it would require something in OpenCPN or a plugin to constantly monitor waypoint updates in my Garmin.

thanks,
Ron

NMEA does not transmit waypoints. But it does transmit your current location at least every second, so just mark your waypoint in OpenCPN as you sail.

If your Garmin supports exporting waypoints to an SD card, they’re probably in a .gpx file (called current.gpx on Garmin handhelds) that can be easily saved on your computer and opened/edited in OpenCPN. But this method may be different on non-handheld devices.

[CapnRon47]

Good point on the NMEA sentences; I had not thought about that. I have OpenCPN on an Android tablet and I can set waypoints using the touch screen, it is just not as convenient as a having a button (or an icon) to touch. The current plugin that supports an external command thru an icon does not work for internal OpenCPN commands.

thanks,
Ron

[CapnRon47]

I was just reading the manual for one of the new Garmin ChartPlotters and it says one of the NMEA 0183 sentences that is available is GPWPL - Waypoint location. I am looking at an EchoMap 70 series (7" screen). My current Garmin Chart plotter is about 10 years old and does not seem to have this feature. the newer Garmin ChartPlotter also already has a race start timer (NOTE: I have no affiliation with Garmin, just a curious user). So maybe I just need to upgrade my chart plotter!

thanks,
Ron

[RhythmDoctor]

Originally Posted by CapnRon47

I was just reading the manual for one of the new Garmin ChartPlotters and it says one of the NMEA 0183 sentences that is available is GPWPL - Waypoint location. I am looking at an EchoMap 70 series (7" screen). My current Garmin Chart plotter is about 10 years old and does not seem to have this feature. the newer Garmin ChartPlotter also already has a race start timer (NOTE: I have no affiliation with Garmin, just a curious user). So maybe I just need to upgrade my chart plotter!

thanks,
Ron

Oops, looks like I was wrong. Thanks for pointing that out.

New gear often corrects one problem and cause$ another one.

[rgleason]

https://opencpn.org/wiki/dokuwiki/do...nmea_sentences

• xxWPL - Waypoint Location Used to send routes and waypoints up to a GPS receiver. OpenCPN does not process these sentences as input.

1. Latitude
2. N or S (North or South)
3. Longitude
4. E or W (East or West)
5. Waypoint Name

[nohal]

Originally Posted by CapnRon47

I was just reading the manual for one of the new Garmin ChartPlotters and it says one of the NMEA 0183 sentences that is available is GPWPL - Waypoint location. I am looking at an EchoMap 70 series (7" screen). My current Garmin Chart plotter is about 10 years old and does not seem to have this feature. the newer Garmin ChartPlotter also already has a race start timer (NOTE: I have no affiliation with Garmin, just a curious user). So maybe I just need to upgrade my chart plotter!

thanks,
Ron

Just before you invest in a new plotter and get disappointed. Yes, there is the WPL sentence. With OpenCPN, two things may be happening with it:

a) Nothing at all and it is completely ignored as we have absolutely no idea what does it mean that such a sentence appeared in the message stream and the message itself has insufficient semantics to reveal it's purpose. This is the default behaviour.

b) It is treated as an APRS position report, similar to AIS, as used in HAM connected systems. This has to be enabled in the Toolbox on Ships/AIS Targets tab.

If the newer Garmin plotters emit the WPL sentence under some circumstances (Do they? If they do, under what circumstances?), we can certainly implement support for this use case.

Pavel

[AedanC]

My Garmin seems to emit something on NMEA2000 that my Vesper XB6000 converts to something, (presumably a WPL sentence), that OpenCpn displays as an APRS position report. It sends this when I activate the “Navigate to this point” function on the Garmin and it shows the destination point.

[rgleason]

Aedan, perhaps you could plug your OpenCPN computer into the XB6000 USB port and do a recording of this action and attach it here?

[CapnRon47]

It appears that the newer Garmin (and B&G Vulcan) Chartplotters already have sailing assist instrument gauge features; such as a wind gauge display and race start line charting and timers. My use of OpenCPN, in the past, has been (mostly) as a navigation planning tool on a computer at the nav station. I would have to load the waypoints from my planned route onto an SD card to transfer them to the older Garmin I have at the helm. It seems that OpenCPN already supports this uploading of waypoints to the newer Garmin chartplotters, so I am happy!

The Garmin EchoMap users manual, which I downloaded, does not indicate under what conditions it transmits the WPL sentence, but it does accept them.

thanks,
Ron

[Captain_Bobby]

Is there a way to overlay EOSDIS satellite images?

[yachtvalhalla]

Originally Posted by Captain_Bobby

Is there a way to overlay EOSDIS satellite images?

I doubt that doing so would be much assistance in navigating due to the poor resolution.


See image.


Terry