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Old 07-04-2013, 17:33   #61
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Re: weather routing

I've enjoyed this discussion.

QtVlm Route Manager has an wind direction icon at each waypoint and some Gribb conditions information available. It was helpful, but I found the traditional isocroyns and routing more useful for some reason during the Vlm Vendee, of course I had internet and was ashore. QtVlm does permit control of start times and Maitai has taken those flexibilities even further in the new version (haven't used yet). My impression of QtVlm was very positive as far as a tool for sailing goes.

I think PjotrC's thoughts about simplicity are good, 15,000 miles is a long way to sail. I think Sean is on the right course for now (It certainly isn''t worthwhile changing goals now) and in time the interface and calcs will improve for a given purpose (maybe two modes?)

Quote:
Well in that case, it should be possible to just have the program use a defined route, at different times and give results (like wave height and winds along the way.. how much is beating.. how long it takes). This would be much faster to compute as well.
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Old 08-04-2013, 03:48   #62
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Re: weather routing

With reference to PjotrC’s input, I believe that it would be very useful to have built-in a tool to find the optimum weather window for a safe passage. A scenario that comes to my mind is when waiting in Falmouth for a passage to La Coruna in Spain and a row of weather system comes across he northern Atlantic. When is the optimum time to start?

The weather routing could run through the route calculation a number of times with 2, 4, or 6 hour intervals. The route planner could calculate as long as there are grib data available. The data could be present in a schematic form as shown below. Different colors could show which is the fastest, the shortest and the ones which have wind and wave data that are above the limit set in the program.
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Old 08-04-2013, 05:10   #63
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Re: weather routing

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Originally Posted by Taarnskov View Post
With reference to PjotrC’s input, I believe that it would be very useful to have built-in a tool to find the optimum weather window for a safe passage.................
YES this is what I like to have!!!
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Old 08-04-2013, 06:45   #64
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Re: weather routing

Agreed, this is the way I have tried to use gribs and weather routing during leasure sailing.

I support this request!
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Old 08-04-2013, 07:18   #65
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Re: weather routing

+1 from me on this request
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Old 08-04-2013, 12:35   #66
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Re: weather routing

I vote YES for this feature.
To find the safest window to sail from one harbor to another one.
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Old 08-04-2013, 13:30   #67
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Re: weather routing

I would like to get Sean's Wx_Routing plugin working on Windows first. I am sure it will be useful in whatever form, so right now I don't care at all what features are or aren't in it. In my opinion this discussion is useful for the future, and interesting, but academic. I don't think we have the luxury of 'voting', its more like making suggestions unless you want to help program! (Which I would very much like to do, but it is still feeling a little deep for me. Haven't found the hooks yet.)
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Old 08-04-2013, 15:44   #68
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Re: weather routing

Quote:
Originally Posted by Taarnskov View Post
With reference to PjotrC’s input, I believe that it would be very useful to have built-in a tool to find the optimum weather window for a safe passage. A scenario that comes to my mind is when waiting in Falmouth for a passage to La Coruna in Spain and a row of weather system comes across he northern Atlantic. When is the optimum time to start?
I agree. This would also apply for leaving harbors which have tidal currents. There are a ridiculous number of scenarios.
Quote:
The weather routing could run through the route calculation a number of times with 2, 4, or 6 hour intervals. The route planner could calculate as long as there are grib data available. The data could be present in a schematic form as shown below. Different colors could show which is the fastest, the shortest and the ones which have wind and wave data that are above the limit set in the program.
That would be very easy to implement, it would just take that much more processing time, but now that I have improved the performance of the algorithm considerably, (it's about 20 times faster) I can probably improve performance some more.

Running it 20 times (for each possible start time) might take a minute or two to compute for each possible start time for a 3 day passage.

As far as max swell and wind goes... currently it will try to sail around these areas even if it takes longer. So, there are two possible ways to avoid bad weather.. by waiting in port, or by sailing a longer course. Usually sailing longer will get you to the destination sooner, but spend more time at sea, so both ways should be supported.

It would be cool to somehow interpolate between starting time routes to give a smoother transition between slices. Then I can add the timeline slider (like for the grib plugin) for start time. I'm getting worried this plugin could be a bottomless pit of work.

Quote:
Originally Posted by rgleason View Post
I would like to get Sean's Wx_Routing plugin working on Windows first. I am sure it will be useful in whatever form, so right now I don't care at all what features are or aren't in it. In my opinion this discussion is useful for the future, and interesting, but academic. I don't think we have the luxury of 'voting', its more like making suggestions unless you want to help program! (Which I would very much like to do, but it is still feeling a little deep for me. Haven't found the hooks yet.)
Could you please try to compile again and post build errors? I tried to fix the ones from last time it should be getting pretty close now. If you can pull with git and get something then I have made changes.
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Old 08-04-2013, 18:46   #69
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Re: weather routing

Sean, I really think this is getting closer. I've included both the git effort to "pull" an exact version of what you have for sean/grib_enhancements so you can see what I did. (I unwisely named my local as 'sean/grib_enhancements' which creates an ambiguity for git, but I've managed to get around that I think. Next time I willl scrub the entire thing and start fresh if you think that would be best. This time I will name the local 'rick/grib_enhancements' just as I noticed thomas did.)

Anyway the git info is there for you if you want. Also I've included the whole MSVC Debug Output file so I don't delete anything vital. (I had run Rebuild several times to reduce the size of this output)

Hope this helps you. I am going to try looking at your code to see if I can start to understand it. Good training I think.

Thanks. Rick
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File Type: doc Weather_routing-MSVC-Debug-Build-Output-5.doc (11.1 KB, 44 views)
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Old 08-04-2013, 19:14   #70
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Re: weather routing

So all the errors now are linker based. I think this is because of the way windows deals with linker symbols. I think I fixed this mostly now in git.. try again. Thanks
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Old 09-04-2013, 04:42   #71
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Re: Wweather Rrouting

Good Morning Sean,

Here are the resullts. I've tried to document
Git and cmake in one document
MSVC Debug ReBuild Output in another.

If you see something I've done wrong I am sure you'll let me know. Thanks.
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File Type: doc Git-Sean-Grib_enhancements-2.doc (22.3 KB, 41 views)
File Type: doc Weather_routing-MSVC-Debug-Build-Output-6.doc (24.0 KB, 40 views)
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Old 09-04-2013, 13:15   #72
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Re: Wweather Rrouting

Thanks for considering my little note. Sure, I do not want to distract anyone from fascinating and useful field of optimizing route for speed. I just wanted to spark some interest in overall route planning tools, based on GRIB data. The simple tabular representation of various factors per waypoint can be very useful, and one can indeed imagine a simple bar graph for a fixed route, showing total time and percentage of motoring time, tabulated for say 3 hour intervals from now for some 2-3 days ahead.

QtVlm shows nicely the wind data, but I'd like stepping through departure times and comparing results a little easier.

Below is a sample of what I am using now, and it is quite close to what I want... I play with the departure time, looking through the table, mainly for the "foul", "scant" and "close" wind occurences, and for motoring legs. As I did not code in the support for motoring, I use an "xx.11" knots entry in the polar diagram, so I readily see, where I would need to motor. Sometimes I use another polar diagram for stricly non-motoring passage, where appropriately low VMG is given for "foul wind" legs. Inaccurate as it is, it works well in practice. In the example below, even without accounting for the Agulhas current, and a bit different actual wind conditions, the time to arrive at Cape Agulhas was within a couple of hours from this simple prediction. Leaving a little later would save us the turbulent first night, but we were tired of waiting already, and we wanted to leave on falling tide...

The interest for precipitation is new indeed, somehow lots of rain does not feel so much fun as it used to...

P.
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Old 09-04-2013, 15:05   #73
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Re: Wweather Rrouting

PjotrC Thanks for the screenshot, it helps me understand what you are talking about. It seems like what you'd like is a cross between Route Manager X Gribs X WeatherRouting in tabular form like Routemanager. Sort of an enhanced RouteManager with certain additional fields or columns for each waypoint.
What are those columns that you'd like?

Also do you find the Tree view for Gribs useful, or would it be okay to just have a drop down selector with a button to browse to a new directory?
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Old 09-04-2013, 16:03   #74
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Re: Wweather Rrouting

Right now, this is the goal! Posted by Sean earlier:

http://cdn.cruisersforum.com/forums/...4&d=1363390468
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Old 09-04-2013, 16:20   #75
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Re: Wweather Rrouting

Quote:
Originally Posted by rgleason View Post
Good Morning Sean,

Here are the resullts. I've tried to document
Git and cmake in one document
MSVC Debug ReBuild Output in another.

If you see something I've done wrong I am sure you'll let me know. Thanks.
No.. it is the way visual studio exports variables.. very confusing. There are only a few linker errors now.. no compile errors. I have changes in git now which should fix these.

I really only need the build output. Thanks for the testing.. I think this is getting very close.

Quote:
Originally Posted by PjotrC View Post
Thanks for considering my little note. Sure, I do not want to distract anyone from fascinating and useful field of optimizing route for speed. I just wanted to spark some interest in overall route planning tools, based on GRIB data. The simple tabular representation of various factors per waypoint can be very useful, and one can indeed imagine a simple bar graph for a fixed route...
Currently, you can export the weather route to opencpn route and view it in the route manager like that.
Quote:
QtVlm shows nicely the wind data, but I'd like stepping through departure times and comparing results a little easier.
For whenever I eventually get around to implementing multiple departure times (If you want to do it, have at it.. just let me know so we don't duplicate), we need a table with all the departure times, maybe as separate rows, then columns for arrival time, total time, average speed, max wind, max swell, percentage of time upwind etc..
Quote:
Below is a sample of what I am using now, and it is quite close to what I want... I play with the departure time, looking through the table, mainly for the "foul", "scant" and "close" wind occurences, and for motoring legs. As I did not code in the support for motoring,... uple of hours from this simple prediction. Leaving a little later would save us the turbulent first night, but we were tired of waiting already, and we wanted to leave on falling tide...
So maybe in that case, specify departure times, in a list, but be able somehow synchronize these to a tidal cycle
Quote:
The interest for precipitation is new indeed, somehow lots of rain does not feel so much fun as it used to...
I'll consider it as low priority.
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