Weather Routing

[ludwig_kilian]

I am sometimes experiencing calculation failed based on polar file although the polar covers all 360 degrees. The route ends - fails on land or the coast. What am I missing an how do I configure the plugin to fix this?

thank you

[rgleason]

ludwig, after completion of a routing right click and pick "Weather Table"
You can select the data types you'd like to see.
I am not sure the values are at the correct magnitude.

[ludwig_kilian]

Hi

The weather table gives more local data and together with the course I can calculate the wind angle relative to my course.

Is the wind angle relative to my weather route course available and reported anywhere?

thank you

[rgleason]

Set one of the values to AWA

[ludwig_kilian]

I think I am missing something. I cannot change the values. Nothing happens on left or right click or tab somewhere on the weather table. I cannot select one of the existing values. How do I get a table of possible values to select e.g. AWA. in the weather table?

[rgleason]

Whoops, sorry Go to the weather_routing Config menu. Find "View" and then "Plot".
Or use "Ctrl+P" Then a set of charts similar to the plugin SweepPlot appears.
Now just hit one of the dropdowns and select.

See photo.

[SoggyPaws]

First let me say that I love OpenCPN and I full appreciate the thousands and thousands of hours that have gone into creating and enhancing this fabulous tool.

But Wow, I am totally unable to get this weather routing thing to work. About once a year I try it and get so frustrated that I give up. I am very savvy with OpenCPN, pretty computer savvy, and somewhat "weather routing" savvy. I can usually muddle through without reading the directions and figure things out, when others can't. A year ago, when I was frustrated, I posted on the SCCA Facebook page "does anyone know how to use the weather routing in OpenCPN?" I was surprised that I go NO RESPONSES. That tells you something.

So it was with great excitement that I noticed and updated plugin on the plugins page. We are tracking friends on a tough upwind trip in light air, and trying to give them some routing advice. Plus we regularly do short ocean passages in the western pacific, and I'm looking forward to have an onboard replacement to the routing I used to do with Maxsea.

So I've got 4.4.0 and the latest Weather Routing plugin I downloaded from the Plugins page 2 days ago (1.10.x). I'm on Windows 10.

It was with the usual confusion that I tried to figure out how to start from scratch, with a boat configuration (this is where I've always gotten hung up before).

But I muddled around and used (I think) the default boat.xml and loaded a polar for first a Contessa 33 and then (later, when that didn't seem to be working), a Crealock 34.

I figured out how the start and end thing works (and do agree that there's a bug in deleting a routing point as reported by the OP a few pages back).

Then I clicked Compute.

Twice I actually got a routing, which was a straight line (straight upwind) at about 5-6 knots. Note: That ain't happening under our prevailing conditions, especially not with a 33 or 34 ft boat, unless we're motoring (and even then not!). Is there a motoring provision??? I can't find it (like "motor if speed drops below X knots, and motor at Y knots).

The rest of the time, I click "compute" and nothing happens... no error, no progress window, nothing.

Even when I did get a routing, I got none of the "isochrons" or anything displayed on the screen (NOTHING like the screen shot RGleason posted recently on this thread)... almost nothing happened until I clicked Export on the screen, and then the plot showed up as a route on my chart. I can't get it to do anything now, so I can't even show you that.

Some screen shots are attached, and the WeatherRoutingConfig file is too large to attach as a txt file, so here it is:

<?xml version="1.0" encoding="utf-8" ?>
<OpenCPNWeatherRoutingConfiguration version="1.10" creator="Opencpn Weather Routing plugin">
<Position Name="Current Posn" Latitude="1.08016" Longitude="147.34272" />
<Position Name="Kapinga" Latitude="1.18071" Longitude="154.68804" />
<Position Name="Boat" Latitude="1.94060" Longitude="148.15710" />
<Configuration Start="Boat" StartDate="9/20/2016" StartTime="10:30:00 PM" End="Kapinga" dt="7200" Boat="C:\ProgramData\opencpn\plugins\weather_routi ng\Boat.xml" Integrator="0" MaxDivertedCourse="90" MaxCourseAngle="180" MaxSearchAngle="120" MaxTrueWindKnots="100" MaxApparentWindKnots="100" MaxSwellMeters="20" MaxLatitude="10" TackingTime="0" WindVSCurrent="0" AvoidCycloneTracks="0" CycloneMonths="1" CycloneDays="0" UseGrib="1" ClimatologyType="4" AllowDataDeficient="1" WindStrength="1" DetectLand="1" DetectBoundary="0" Currents="0" InvertedRegions="0" Anchoring="0" FromDegree="0" ToDegree="180" ByDegrees="5" />
</OpenCPNWeatherRoutingConfiguration>

If you can point me in the right direction, I'd appreciate it. I'd love to get this working. It's my favorite thing to do on passage (play with routings). Meanwhile, I'm using Fastseas.com to route for my friends... 5 minutes from never using it before and I got a believable routing out. Pretty impressive.

Sherry s/v Soggy Paws
In Palau (western Micronesia)

[seandepagnier]

From what I can tell, your grib has very light winds, and the polar you selected probably doesn't define boat speed below a certain wind speed.

As for sailing directly into the wind, I need more information.


As far as "5 minutes and a believeable route" sounds very nice, but how can we know if this route is actually the best possible one?

If you can give some constructive input on how to make the plugin more user friendly, also patches are welcome

[ludwig_kilian]

Thank you that makes sense. I see the SOG is correctly represented. The scale of AWA puzzles me, I get numbers like 2131.0 till -2129.6. I am not sure how to translate these in to wind angles.

I assume the sharp dips are when a tack is forseen.

I assume that the x-axes shows the time since the start, is this a correct assumption? Is there another simple way to correlate position on the map to a position in the sweetplot-like map?

thank you for your patience

[rgleason]

Ludwig,

Sean, the author, often reads this thread, so hopefully he'll respond.
We appreciate your using the plugin and asking questions, as it hones both the user and the program. We are very lucky Sean has created such an awesome plugin.

Some of the scales do confuse me, and perhaps Sean has seem this too and will have an answer or a fix

I believe the X axis is time.
It would be nice if your cursor position on the route somehow showed in the Plot, but the plots are not completely interactive with the chart window.

I have not had time to really dig into the plugin lately, but we really need to update the documentation for Weather_routing because the plugin has both expanded and simplified. I wonder if you would be able to help?

[SoggyPaws]

OK, I am getting somewhere.

It appears that the polar files need a zero/zero row/column, though almost every file that's in the supplied "polars" folder doesn't have one. It would be nice if the program would "assume" a zero/zero row/column, if that's what it needs to be able to handle low wind scenarios.

I have a couple of questions:

1. I am using Saildocs for my gribs, and I get wind in one grib file and current in another (either RTOFS or OSCAR). Is there a way to tell the plugin to use both files, or do they have to be in ONE GRIB file. I have found that I can use Climatology for the current, but in this case the currents shift, and they are strong, and they make a significant difference to the routing solution in light winds.

2. Is there documentation about using multiple polar files, and what all the "crossover" stuff is? I see one set of polar files (with no zero/zero entries) in the polar directory for Bristol 28 that implies this is for different sail combinations, but I have no idea how to properly use it. Can you point me to a discussion on the concept?

3. Is there a motoring feature? I see no configuration for it. (ie, start motoring if wind drops below X knots and motor on direct course at X knots)

4. Is there ANY logging that is done that could be viewed to try to see what the program is balking at?

5. What are the brown arrows and the black arrows representing? When it's computing, I see the brown arrows creep across the routes as if they are isochrons, but they don't look like isochrons at all (is there a setting that will display them as isochrons rather than as brown arrows?) The black arrows appeared after the routing was finished, I think. See screen shot.

And some comments/bugs:

1. Editing the Polar on screen on Windows doesn't work, as when you try to save it, it tries to save it (without asking where you want to save it) in C:\Program Files (x86)\opencpn\... vs C:\ProgramData\opencpn, and Windows doesn't like that...it gives an error and won't save it.

2. It would be nice to be able to hover over a configuration in the Configuration list and see the XML file name and the Polar file name.

3. It looks like the multiple configurations are oriented at Departure Planning, but in my case, I am using it for different boats with significantly different characteristings, possibly in different locations (just me and a friend sailing on the same ocean, talking by SSB).

I'd be happy to help with documentation once I figure it out... Tooltips would go a long way to making it easier for a newbie to start using it.

Thanks,
Sherry

[Littlechay]

Ditto the comments by Soggy Paws.

I can't seem to get a routing to work due to "polar fail" it fails instantly if land detection is turned on, gets a day or so into a route if land detection is turned off.

I've edited the polar to put in TWD and TWS columns/rows for 0 (all 0). Made sure the polar has winds for the range in the grib.

When I view the plot for the partial route that I get the values are garbage and the hours value along the top makes little sense .. e.g. 1d 34h does this mean 1d 10h (34h) ?

The plot shows a fairly constant wind direction when if fact it is changed through 180 degrees or so during the period.

The only way to change a polar without running OCPN in administrator mode, on Windows, seems to be to manually edit the polar in text editor as OCPN doesn't have permission to write to the default location.

When GRIB is unselected and using climate data land detection seems to work more or less. At least a route is created with some shortcuts over land. I think I have the high res Ghhs file installed but need to check this.

Attached a screen shot, polar file, and grib file. I was routing between a location off Stanley and one near Isla Picton in the Beagle Channel. (remove .doc from the GRIB and Polar files to correct the file names).

[ludwig_kilian]

Thank you, happy to help out with documentation, as soon as understand a bit more what is happening. I have the feeling I am not on top of this yet.

Any suggestions how/where to learn more is appreciated.

[seandepagnier]

Originally Posted by SoggyPaws

OK, I am getting somewhere.

It appears that the polar files need a zero/zero row/column, though almost every file that's in the supplied "polars" folder doesn't have one. It would be nice if the program would "assume" a zero/zero row/column, if that's what it needs to be able to handle low wind scenarios.

What would be better? To modify all the polars? To automatically add if missing? Prompt user?

I have a couple of questions:

1. I am using Saildocs for my gribs, and I get wind in one grib file and current in another (either RTOFS or OSCAR). Is there a way to tell the plugin to use both files, or do they have to be in ONE GRIB file. I have found that I can use Climatology for the current, but in this case the currents shift, and they are strong, and they make a significant difference to the routing solution in light winds.

You may concatenate the grib files into a single file, eg:
$ cat file1.grb file2.grb > combined.grb

This allows rtfos with oscar together.

2. Is there documentation about using multiple polar files, and what all the "crossover" stuff is? I see one set of polar files (with no zero/zero entries) in the polar directory for Bristol 28 that implies this is for different sail combinations, but I have no idea how to properly use it. Can you point me to a discussion on the concept?

There isn't documentation on this feature, but essentially you can have as many polars as sail plans and the fastest polar is used.

Whenever a sail change occurs it is also plotted on the course.

If the polar doesn't define a speed it cannot be used in those conditions.

3. Is there a motoring feature? I see no configuration for it. (ie, start motoring if wind drops below X knots and motor on direct course at X knots)

Yes, because you may create a specific motoring sailplan with a polar defining the boat speed in the desired conditions. You may only define speeds up to 5 knots of wind, or 10 knots into the wind for example.

4. Is there ANY logging that is done that could be viewed to try to see what the program is balking at?

?

5. What are the brown arrows and the black arrows representing? When it's computing, I see the brown arrows creep across the routes as if they are isochrons, but they don't look like isochrons at all (is there a setting that will display them as isochrons rather than as brown arrows?) The black arrows appeared after the routing was finished, I think. See screen shot.

?

And some comments/bugs:

1. Editing the Polar on screen on Windows doesn't work, as when you try to save it, it tries to save it (without asking where you want to save it) in C:\Program Files (x86)\opencpn\... vs C:\ProgramData\opencpn, and Windows doesn't like that...it gives an error and won't save it.

I think I fixed this in latest git no?

2. It would be nice to be able to hover over a configuration in the Configuration list and see the XML file name and the Polar file name.

the xml of the boat? Would it do to just display the boat name as an optional column?

3. It looks like the multiple configurations are oriented at Departure Planning, but in my case, I am using it for different boats with significantly different characteristings, possibly in different locations (just me and a friend sailing on the same ocean, talking by SSB).

it's not specifically for departure planning as you have found. In the batch mode, you can actually generate for multiple boats as well as different departures for example.

I'd be happy to help with documentation once I figure it out... Tooltips would go a long way to making it easier for a newbie to start using it.

More feedback on tooltips is needed.

Originally Posted by Littlechay

Ditto the comments by Soggy Paws.

I can't seem to get a routing to work due to "polar fail" it fails instantly if land detection is turned on, gets a day or so into a route if land detection is turned off.

Do you have highest resolution gshhs installed? It would be nice if
plugin detected which resolution...

I've edited the polar to put in TWD and TWS columns/rows for 0 (all 0). Made sure the polar has winds for the range in the grib.

When I view the plot for the partial route that I get the values are garbage and the hours value along the top makes little sense .. e.g. 1d 34h does this mean 1d 10h (34h) ?

That seems a bug to me.

The plot shows a fairly constant wind direction when if fact it is changed through 180 degrees or so during the period.

The only way to change a polar without running OCPN in administrator mode, on Windows, seems to be to manually edit the polar in text editor as OCPN doesn't have permission to write to the default location.

Is this with latest git?

When GRIB is unselected and using climate data land detection seems to work more or less. At least a route is created with some shortcuts over land. I think I have the high res Ghhs file installed but need to check this.

Attached a screen shot, polar file, and grib file. I was routing between a location off Stanley and one near Isla Picton in the Beagle Channel. (remove .doc from the GRIB and Polar files to correct the file names).

[Littlechay]

Do you have highest resolution gshhs installed? It would be nice if
plugin detected which resolution...

I don't know. I thought I downloaded the high res version and the background chart is fairly detailed but the weather routing seems to route around large tri-angles only.

How can I check which version is installed?

Is this with latest git?

No with the version from the plugins download page. (1.10).