Weather Routing

[ALROCHARARI]

Have send following email to o-charts guys:

I'm using your o-charts charts for sailing and would like to see the coastlines loaded in OpenCPN aligned with the quality of the maps you provide.
Would it be possible for you to create the corresponding costlines for the vector maps you provide?
Would it be useable within OpenCPN? I could imagine that this would require a small cost update for your charts.
Looking like a good business case for you. No?

This would be a great improvement and would avoid a lot of issues when trying to optimise route calculations.
Please have a look at the following small video to understand the point.
https://www.dropbox.com/s/cblts175gl...38-02.mkv?dl=0

In addition, if you have the possibility to make these with accurate depths information, this would allow even more accurate sailing simulation options.
Depths at 0m, 0m20, 0m40, 0m60, 0m80, 1m, 1m20, 1m40, 1m60 ... up to 10m in different files to allow selection of ideal file for boat selected and tide estimations.

Would be even better.

[Ratty1978]

Weather Routing1.13.44.0 on June 14, 2022 works in Windows 11/Dell 7220. Had a few quirks. Couldn't find polars from the previous version, so retyped (I have the old US Sailing polars for the boat). Default for position is Degrees, Minutes.decimal. Not sure it would read Degrees Minutes Seconds.decimal, but I can do the math.

Particular route in mind was easy with today's conditions, straight course, broad reach, 25 nm 4 hours. But it worked.

One issue. I'm on Lake Michigan. So I can go 60 nm east northeast and 270 nm north northeast, offshore, out of sight of land much of the way. I need to uncheck "Detect Land" for weather routing to work. I suspect it's because I'm at 42 N 87 W and not on an ocean. There's a famous Ted Turner story, while in a storm, retracting his earlier comment about the Great Lakes being millponds. For the course I tested, it did take me inside a marked wreck and just offshore a point. So an operative "stay offshore" function would be interesting to have. A navigator should be paying attention anyway, though. Hitting the shifts when crossing the Lake would be good enough when racing.

[rgleason]

Good suggestion!!!!!


I have the same issue for many programs on Windows.

My quick fix for Weather Routing is to delete the following from the [PlugIns/WeatherRouting] section of opencpn.ini:

[Ratty1978]

Just ran it again, upgraded OpenCPN to 5.6.2 from 5.6.0 and ran routing later in the day (3 hours). This time it would route me over the point of land. It's a record breaking hot day which makes me wonder if the GRIB files figured out seabreeze. Probably not and probably just modeled gradient wind clocking a bit.
Same thing with "Detect Land" -- had to uncheck to get Configuration - Compute

[rgleason]

I've sailed the Mac a number of times in your "Millpond" and seen the storms do a 360 within a blink of the eye.


Are your GHSSH High Res? You need to download those. I generally turn off charts. I did some routing tests in Lake Michigan, due to others having troubles, but I found that routing was possible, however there are issues with Land Detection, I don't remember exactly what. Let me find the link.


See https://github.com/rgleason/weather_...g_pi/issues/71

Bug (with workaround): Inland Waters & Lakes Land Detection Bug #71

https://www.cruisersforum.com/forums...ml#post2827957

WORKAROUND:
The workaround is to make a BOUNDRY with Ocpn-Draw and enable Boundaries in Weather_Routiing.
https://www.cruisersforum.com/forums...ml#post2826862

Originally Posted by Ratty1978

Just ran it again, upgraded OpenCPN to 5.6.2 from 5.6.0 and ran routing later in the day (3 hours). This time it would route me over the point of land. It's a record breaking hot day which makes me wonder if the GRIB files figured out seabreeze. Probably not and probably just modeled gradient wind clocking a bit.
Same thing with "Detect Land" -- had to uncheck to get Configuration - Compute

[ALROCHARARI]

Suggestions:

1. Is-it possible to have distance from ground with decimals?
We sometimes have to go through straits and 0.1Nm is perfectly acceptable for sailing normally.

2. It should be possible to customise the number of wind barbes displayed on the route calculated by WeatherRouting plugin. For example 1 every 5 isochrones or a parameter depending on the zoom factor.
Objective is to avoid a massive "line" all along the route when zoom is not big enough.

Best regards,
Raoul

[bcn]

Originally Posted by ALROCHARARI

Have send following email to o-charts guys:

We will answer here, as it may be interesting for all others as well.



A finer small scale background chart or coastline chart would be great of course.
Question is just who edits it - edit does imply as well to define a format OpenCPN and plug-ins know about and to maintain that chart (set).
o-charts is not a chart editor, just the chart outlet of OpenCPN for OpenCPN. With that we are more than busy.


Of course would we be happy to host such a chart if somebody from the OpenCPN community would take the challenge to generate some quality shoreline chart.
Btw.: OSM (OpenStreetMap) has shorelines. The task is to join the pieces and quality check the result. In a format useful for OpenCPN.


The other aspect is to use chart objects from existing vector charts for the (weather) routing. You were mentioning depths. There are more like keep out and protected zones or the TSS resulting in constraints for routing.
In the case of licensed charts like S-63 or oeSENC the corresponding plug-in would need to deal with delivering the required information.


Hubert

[hasse_A]

I have an issue where the router is unable to finish the route to the destination. This has nothing to do with the previous hanging problem.
The router calculates in steps closest position to the goal. If the rout needs to go outside the area of isodistance, is this the correct naming ?, it can't continue. To force the route from land I introduced a boundary.
Is this something that is known and just the way it works or can it be addressed.
To illustrate the behavior I have attached a plot of a route from Baiona to La Coronia.

/Hans

[rgleason]

Originally Posted by hasse_A

I have an issue where the router is unable to finish the route to the destination. This has nothing to do with the previous hanging problem.
The router calculates in steps closest position to the goal. If the rout needs to go outside the area of isodistance, is this the correct naming ?, it can't continue. To force the route from land I introduced a boundary.
Is this something that is known and just the way it works or can it be addressed.
To illustrate the behavior I have attached a plot of a route from Baiona to La Coronia.

/Hans

Hans I think you need to shorten the interval and adjust max diverted course. Without having it to work with not sure what the problem is, but it will complete, provided your grib is big enough.

[hasse_A]

Originally Posted by rgleason

Hans I think you need to shorten the interval and adjust max diverted course. Without having it to work with not sure what the problem is, but it will complete, provided your grib is big enough.

You are absolutely correct. Opening up max diverted course fixed the problem.
This was a great help to me as I am weatherrouting a number of boats.
Thank you.

/Hans

[rgleason]

As the calculated route moves into closer quarters, islands, bays, rivers, and other GSHHG complicated landmasses you have to increase calculations using those two controls time interval and max diverted in order to complete.

Weather routing in its current state is not good at adjusting this on the fly when it is having trouble completing or getting around a landmass like Cape Cod Provincetown Harbor. There is a Issue by Did-g which is suggesting a way to handle this Slow Start https://github.com/seandepagnier/wea...ng_pi/pull/205 I have suggested a "Slow Steps" tab for start, finish and other areas of difficulty. Read this issue you will learn some important things about WR.

Just move starting and ending point out away from those areas and run your calcs it will be close enough for cruising. If you are using it for routing racers, that is another matter.

Originally Posted by hasse_A

You are absolutely correct. Opening up max diverted course fixed the problem.
This was a great help to me as I am weatherrouting a number of boats.
Thank you.

/Hans

[rgleason]

A newly updated version of weather_routing is in PIM master catalog. Just updates the frontend2

[hasse_A]

Originally Posted by rgleason

A newly updated version of weather_routing is in PIM master catalog. Just updates the frontend2

I updated and got weather_routing version 1.13.46.0
Ia also updated climatology to 1.4.46.0

What was the reason for this weather_routing update ?
Was it the problem the hanging ?

/Hans

[rgleason]

Updates include new versions of frontend2 which handles cmake and all the various OS builds which keep changing over time, some start failing due to underlying libs being retired etc. I try to keep these to every 3 months but that is pretty impossible.
There can also be improvements and fixes in these updates.

[shipahoy]

I get a bit confused by my weather routing results. The boat speed is much higher than the one I specified in the polar. See the example below. This is a simple polar for motoring with max speed of 7 knots, but I get similar results with the sail polar.
I get a boat speed of 10 knots when I was expecting 4 knots. See the attached screenshots.