Weather Routing

[bewitched]

Originally Posted by boat_alexandra

What you want is already implemented in the grib plugin, or do you suggest a new feature?

I think it is a new feature. The grib plugin that has been developed can show the weather across the whole area for each time slot and one can select any point in time and see the weather.

What I'm suggesting is that a single weather barb is put onto the route at each time slot. This will show the weather that will be experienced along the route. For example, in 24 hrs I will be 300nm down the route.. The barb shown at that 300nm point should represent the weather in 24 hrs time. See attached pic. This tells me I am beating into 20 kts for much of the way, dropping to 15kts occasionally. A quick, easy way to understand that i'll be on a J3 and a reef in the main.

Originally Posted by boat_alexandra

This seems simple enough. I just need an additional configuration option which is a wind speed multiplier. It won't do anything with wind direction.

Yes, exactly. With the ability to leave say 5no. plotted routes to compare.

Originally Posted by boat_alexandra

It would be really interesting to somehow get multiple grib files where each have a likelyhood percentage. I have heard of this data but never found a source.

Are you considering different sources for the grib (GFS, CMC), or different resolutions (1deg, 0.5deg etc)?
Personally, I find comparing GFS vs CMC models a worthwhile exercise.

[bewitched]

Originally Posted by rgleason

Bewitched I agree with some changes. We need a precise list of terminology that applies to OPENCPN. I suggested this some time ago but did not persue it. I had some sources for definitions. Can you start a new page in the manual and leave a link here?

Errr...I could make a start..

Can you pm me your sources.

Also, how do I start a page? is there a format template? Is there a review process?

[bewitched]

Originally Posted by wdkester

I agree, except for SET and DRIFT. Neither are self defining and both have more than one meaning to sailors. To me, Current Velocity and Current Direction are reasonably clear and self defining. I would say Tidal Current Velocity if it weren't for the Gulf Stream and other non-tidal currents.

I used Set an Drift as these are the most commonly used terms for water movement. I've seen Tide Set and Tide Drift, also Tide Set and Tide Rate used in instrument packages. In practical terms, it matters little if the movement of the water is caused by the tide, by an ocean current, or the flow of the river.

Originally Posted by wdkester

For a mostly amateur user base, including yours truly, I think we should avoid the acronyms/abbreviations and use the full spelling for all of the above terms.

Yeah, hard to satisfy everyone. I'm most definitely an amateur, but when I talk to other sailors, I do actually say TWD, rather than True Wind Direction.

[seandepagnier]

Originally Posted by bewitched

I think it is a new feature. The grib plugin that has been developed can show the weather across the whole area for each time slot and one can select any point in time and see the weather.

What I'm suggesting is that a single weather barb is put onto the route at each time slot. This will show the weather that will be experienced along the route. For example, in 24 hrs I will be 300nm down the route.. The barb shown at that 300nm point should represent the weather in 24 hrs time. See attached pic. This tells me I am beating into 20 kts for much of the way, dropping to 15kts occasionally. A quick, easy way to understand that i'll be on a J3 and a reef in the main.

That's what I thought but wanted to make sure I understood you. Yes it's a good idea I will try to implement it as an optional display setting.

Yes, exactly. With the ability to leave say 5no. plotted routes to compare.

I implemented this yesterday.

Are you considering different sources for the grib (GFS, CMC), or different resolutions (1deg, 0.5deg etc)?
Personally, I find comparing GFS vs CMC models a worthwhile exercise.

Already supported, it is up to you to load different grib files in the grib plugin. You can simply have identical configurations and compute one, then switch gribs and compute the other. Maybe it's a bit of manual work and could be easier, but the best way to handle this is not entirely obvious.

Originally Posted by bewitched

Errr...I could make a start..

Can you pm me your sources.

Also, how do I start a page? is there a format template? Is there a review process?

No, I do not pm sources. See:
http://github.com/seandepagnier/weather_routing_pi

You can fork the repository into your own github account, make changes and them submit a pull request and I will review it.

[PjotrC]

Originally Posted by boat_alexandra

Yes it's a good idea I will try to implement it as an optional display setting.

Sean...

If you can make it part of Route Properties, I could stop using 2.5 then!

For me this is about all that I really needed, but important is having one-click planning...

Piotr

cf. example at

http://www.cruisersforum.com/forums/...ml#post1643415

[touchngo]

Still struggling with getting ANY of the polars to work;

Hmmm... I pasted a screen grab, but no joy, so will save and attach.

This CSV file is laid out identically to the one I have been trying to use.

Cheers, PT

BTW. The sunodyssey40.csv works fine with qtVlm.

[seandepagnier]

Originally Posted by PjotrC

Sean...

If you can make it part of Route Properties, I could stop using 2.5 then!

For me this is about all that I really needed, but important is having one-click planning...

Piotr

I will only make it work within the weather routing plugin for a computed configuration if that's what you mean.

Originally Posted by touchngo

Attachment 96303

Still struggling with getting ANY of the polars to work;

Hmmm... I pasted a screen grab, but no joy, so will save and attach.

This CSV file is laid out identically to the one I have been trying to use.

Cheers, PT

BTW. The sunodyssey40.csv works fine with qtVlm.

You are using the file incorrectly.

To load a polar you just need to create a new configuration, or edit one (double click on it) and then edit the boat (there is a button "edit" for the boat)

Now, there is a "sail plan polar" tab, and from here, you must select "from file" in the first combo. Now specify the polar you want to use.

[touchngo]

Thanks Sean.

I got it to work, sort of, but it appears to want me to sail directly overland.

I'm attaching two screenshots here. I have checked the detect land box, so not sure what to do next.

Any and all help gratefully appreciated.

Cheers, PT

[seandepagnier]

Originally Posted by touchngo

Thanks Sean.

I got it to work, sort of, but it appears to want me to sail directly overland.

Did you upgrade to the high resolution gshhs data? Try removing all your charts, and look at the world background chart. That's what the plugin uses to detect land.

For that particular configuration you might want to reduce the time step to 15 minutes or less. If you increase much above an hour it will probably get terrible results.

[Gilletarom]

Hello Sean of Epagnier,

I loaded the detailed high resolution gshhs data. I noticed that, thanks to him, for the same configuration also Weather-Routing is able to build a road that does not pass through the land.

But I also see that the road may well come too close to the coast or on a shoal. See screen copy.

It seems to me that there is no way currently in Weather-Routing reflect the depth of water.
Indeed, it seems to me impossible to consider the depth for raster charts.

In your opinion, would it be possible for Weather-Routing takes into account the depth of water when using a vector chart?

Best regards, Gilletarom

[seandepagnier]

Making vector chart depth (and overhead clearance) accessible to plugins is on my todo list, somewhere around number 10 of 20 items.

[Gilletarom]

Originally Posted by boat_alexandra

Making vector chart depth (and overhead clearance) accessible to plugins is on my todo list, somewhere around number 10 of 20 items.

Thank you.

[rgleason]

Bewitched you can login and register on the OpenCPN. Org website. Then add a new page in the outline where you think it should be and enter your the definitions. A new thread with a similar title would be a good place to continue discussion. I will find the sources i had found when i get back to my computer in several days. I can also help you with this endeavor. Best rick

Sent from my SCH-I545 using Cruisers Sailing Forum mobile app

[seandepagnier]

Originally Posted by Gilletarom

Thank you.

Yes, it's needed anyway for the watchdog plugin, and google earth plugin for the future (automatic mapping of only shallow waters at highest resolution)

[bewitched]

Some more definitions Rick

Good Luck!!