Route Planning with GRIB - Work in Progress

[Littlechay]

This is good work. I'm struggling a bit with the interface, as has been mentioned, loosing the grib sync (start time) and the polar plot keeps disappearing just when I think I should be able to mouse over it. But as said the functionality seems to work fine.

I'd this aimed at blue water cruising beware of relying on net access ( same applies to all aspects of opencpn ) most long range cruisers are watching the pennies and taking gribs one a day at best.

Polars, when looking at Polars it's necessary to consider much more than wind - sea state, current, etc. I consider at least two Polars in my head . One for flat water and one for an established breeze. For example I know that in 50knots of new breeze I can make good progress to windward under staysail and fourth reef, as the sea build after a few hours I need to crack off a bit and start wrapping staysail, in a well established 50 knots I might not make any progress to windward at all and may consider heaving to while I wait for better conditions.

Oh yea there is much more to weather routing than Polars, but this is all great and useful stuff.

Chris

[P_Dub]

Got it working on a clean istall. Perhaps one of the parameter I use, is creating the program error. Got a few custom parameters (Currents and Tides, which seems to work fine with 2.5.0). Active I have Dashboard and WMM. Inactive, BSB4, Google Earth, GRIB 1.1, Logbook, NVC and VDR). Hopefully one of you guys will find the culprit... I don't have the expertise to do that.

Cheers!

P_Dub

[PjotrC]

Thanks everybody for your testing effort ...

Originally Posted by nohal

I'm fighting a bit with the UI (constantly loosing the route start timestamp etc. - this definitely needs some touches)

The Departure Time is reset whenever the Properties are displayed for a new (i.e. different from previous) route. It is also reset on creating a new route with the Properties open. Otherwise it should be remembered (it is a property of the Dialog), even when the Dialog is dismissed, but reopened on the same route. During testing indeed one tends to switch routes very often, so this is more noticeable, but in normal work one gets used to this.

When comparing routes, I have - say - two routes starting and ending at the same point, and I know I will be switching between them. Then I mouse copy and save the departure time, to paste it quickly again.

I suddenly discovered that wxWidgets started accepting another format for date: instead of 10/21/2011 one can enter 21-Oct-2011...

And, of course, entering ">" gives you a quick template for a near timestamp, if not just what you want.

I agree this is not ideal, and will try looking for polishing this out.

Originally Posted by Littlechay

the polar plot keeps disappearing just when I think I should be able to mouse over it

You probably refer to the situation when the mouse nears the eye-of-the-wind, and the planned leg enters the dead-muzzler sector. If the polar used is a true sailing polar (near-zero speed in this sector), then you just see the two lay-lines marking borders of the dead-muzzler sector. The rest of the polar (it is an isochrone) gets catapulted off the screen by the suddenly large multiplication factor "1/speed". To avoid computational faults I enforce minimum speed of 0.1 kts ever. Any real speed then will give range a couple of hundred times greater, usually dropping offscreen. The rule of thumb for sailing polars is - keep mousing until you see the complete isochrone. Alternative is to use a polar that gives some (appropriately low) estimate of going upwind.

In the example attached you will see that the planned leg would take 640 hours @ 0.1 kts. Not really...

Originally Posted by P_Dub

Active I have Dashboard and WMM. Inactive, BSB4, Google Earth, GRIB 1.1, Logbook, NVC and VDR). Hopefully one of you guys will find the culprit...

The culprit is, of course, me. Your crash is likely caused by incompatibility of plugin interface between 2.5.10xx (only grib and dashboard, those included in the kit) and 2.5.0, to which all your other plugins are compliant. For testing the new features in 1018 you do not need Dashboard and WMM. Parallel installation and no other plugins, please. It is not even a Beta...

Originally Posted by PjotrC

perhaps too early yet to label any given file "OpenCPN Polar File"...

When I started on this, I just wanted synchronized viewing of GRIBS and the weather forecast in the route plan. I did not intend to use polars. But this is so natural and widely expected, that I included this feature. However, I believe it is still an owner's tool. It is hard to make polars so universal, that they might be used by everybody. Jonas has his -20% rule, Littlechay includes the swell buildup, I want motoring...

If any testers want to play, I attach a sailing and a motor-sailing polar for the same low-performing, but comfortable boat.

Please keep testing....

Piotr

PS. Found some bugs:

1. When seriously overblown, the isochrone is not clipped properly
2. The night palettes make black isochrones invisible
3. I forgot to apply the manual override of "VMG=" in WPT Description

[Gilletarom]

Hello PjotrC,

I want to try your work and I install your last version 2.5.1018.

It seem to run correctly.

But, ...

1°) it impossible to use the other plug-in like VDR, GE, etc ...

2°) I am currently in my house. And therefore, I can not really test your work.
If it were possible to use VDR, it would be possible to test your work with the recordings I made ​​during my sailing this summer.

Can you change this ?

Thank by advance.

Best regards

Gilletarom.

[sinbad7]

Gilletarom..

You have to use Piotr's version in a paralell installation of OCPN for the time being,it is NOT compatible with the other plugins.

Tore

[Gilletarom]

Hello,

Originally Posted by sinbad7

Gilletarom..

You have to use Piotr's version in a paralell installation of OCPN for the time being,it is NOT compatible with the other plugins.

Tore

Obviously, I did a parallel installation.

Too bad that VDR can not be used. Indeed, it can reproduce navigations.

[PjotrC]

Originally Posted by Gilletarom

1°) it impossible to use the other plug-in like VDR, GE, etc ...

2°) I am currently in my house. And therefore, I can not really test your work.
If it were possible to use VDR, it would be possible to test your work with the recordings I made ​​during my sailing this summer.

Can you change this ?

Gilletarom...

Many thanks for trying!

ad 1) In order to use the other plugins, as far as my understanding of plugin technology goes, they just need to be recompiled with the modified interface used in 1018 (no change in plugin source needed). If anyone is willing to try, I will post the source patch.

I do not want to create a parallel distribution, so I just stick to testing the GRIB Planning functionality. If there will be enough interest in this, warranting incorporating into a future production version, I will work towards this. As it will require some effort (hopefully decision-taking only) from Dave, I do not want to press for changes too early, and maybe the interface will get extended independently...

ad 2) I think all the functionality can be tested without live NMEA inputs. It is just a GRIB-based planning tool... The VDR log could be used for automated generation/verification of Polars, but probably with an external tool (spreadsheet), not really worth incorporating into core OCPN.

For looking, how well the simulation predicts the actual passage, I am comparing the results to chosen cases of real tracks recorded underway. I do not have any real VDR recordings.

Replaying actual NMEA data could be used for verifying GRIB forecast quality.

Thanks again,

Piotr

[Littlechay]

I'm testing on windows 7 64bit

I'm struggling to replicate functionality I see in the screen grabs in other posts. I can't display a usable isocrone.

When I select a wp in the route properties dialoge (append waypoint active) the isocrone appears around the waypoint but while the route properties dialogue is open it has focus and I can't work on the chart.

I close route properties but then the isocrone is gone too

How do you display an isocrone on a chart window where the mouse is active?

The second problem is the isocrones don't seem to correctly calculated. Although the maximum speed in my polar is 8.5 knots the radius of the isocrone seems to be greater than about 600 miles. My grib period is 12 hours so that's pretty quick!


I'm probably doing something very stupid

I have gribs for the correct period.
Start date is set in route properties
Speed is cleared (keeps reverting to default by the way )
Route legs are synce'd with grib

Chris

Chris

[PjotrC]

Originally Posted by Littlechay

When I select a wp in the route properties dialoge (append waypoint active) the isocrone appears around the waypoint but while the route properties dialogue is open it has focus and I can't work on the chart.

I close route properties but then the isocrone is gone too

This is more than you ask for, but maybe it helps others, so a full cookbook:

0. If you want to use polars, make sure you have a polar selected in the Tools->Settings Dialog.

1. Open GRIB Dialog and select a GRIB Record for display. The windbarbs should be visible.

2. Open Route Properties on existing route. If there is no route yet, just enter two first waypoints before.

3. Type in Departure Time or ">" for "now" and ENTER. If you type ">" take into account the extra leg between current boat position and first waypoint. If the boat is very far away, it will not join the route within GRIB validity period, so nothing happens...

4. The Plan Speed is always there for route legs that fall outside of GRIB area or validity period. Do not clear this, just set it as default passage speed.

5. If you want to edit the route, just do so, without using the Route Properties Dialog:
- by selecting Append Waypoint to Route (right-click menu anywhere on route)
- by dragging any routepoint (no need to select it in the Dialog)

6. The GRIB display and Wind, Speed, and ETA columns will be automatically updated

If you do not want to use polars, select "none" in Tools->Settings. You will still get the Wind forecast column, using fixed Plan Speed for time calculations.

Originally Posted by Littlechay

The second problem is the isocrones don't seem to correctly calculated. Although the maximum speed in my polar is 8.5 knots the radius of the isocrone seems to be greater than about 600 miles. My grib period is 12 hours so that's pretty quick!

The isochrone depicts all points that can be reached in the same time. One of the isochrone points is set by mouse, the rest is computed automatically according to the polar. The size of the isochrone does not depend on the GRIB period, only on mouse position. In Append Waypoint mode you see the proposed speed and duration of the new leg. It makes sense to keep it below the GRIB time step value.

This behaviour is indeed different than in most WR programs, where the isochrone period is taken from GRIB or set to a fixed time step. But 1018 is a different kind of tool: it assists in manual planning, so it is the navigator driving the process, not the simulation engine. The size of the isochrone depends very much on the chart scale one is working at, so I felt it would be wrong to make it fixed in any way.

Good luck, and thanks for your patience...

Piotr

[Littlechay]

Originally Posted by PjotrC

The isochrone depicts all points that can be reached in the same time. One of the isochrone points is set by mouse, the rest is computed automatically according to the polar. The size of the isochrone does not depend on the GRIB period, only on mouse position. In Append Waypoint mode you see the proposed speed and duration of the new leg. It makes sense to keep it below the GRIB time step value.

Piotr

Hi Piotr,

I Piotr, thanks for your detailed reply. I do understand how the functionality should work, but I can't get it to work.

The problem is that when I click append waypoint I do not get an isochrone. The only time an isochrone appears is when I click on route properties to open the properties dialogue - the isochrone appears where the mouse was located when it entered the route manager window. When I close the properties window the isochrone disappears - end result is that I am unable to work with the isochrone.

The properties dialogue has window focus and moving the mouse has no effect on the chart.

Please see the attached screenshot showing the ischrone located where the mouse entered the manager window.

Regards
Chris

[PjotrC]

Originally Posted by Littlechay

Please see the attached screenshot showing the ischrone located where the mouse entered the manager window.

Chris,

I see now... please open the Route Properties _without_ Route Manager. Just point to the route, rightclick->Route Properties.

Wonderful tool as the Route Manager is, it disturbs sometimes simple things... (for example measuring, or moving around...)

P.

[Littlechay]

Originally Posted by PjotrC

I see now... please open the Route Properties _without_ Route Manager. Just point to the route, rightclick->Route Properties.
P.

Ahh what a great tip! That will be handy for several things I am sure.

I'll have a play now with some real route planning for a tricky bit of weather routing as I head out this weekend (Piriapolis to Stanley). Won't have internet access to report back until arriving in Stanley though.

Cheers

[PjotrC]

New version uploaded to opencpn_2.5.1026_setup.exe - 4shared.com - online file sharing and storage - download

Parallel install and no other plugins, please.

Some bugs fixed, including the night mode and manual "VMG=". Polar clipping still hurts, but less intrusive now.

Wind forecast column extended with descriptive names for expected point-of-sail. I used traditional words from the Age Of Sail because of their brevity.

Enjoy,

Piotr

PS. Does not work well with Course-up mode, but neither does the original GRIB plugin...

[Gilletarom]

Originally Posted by PjotrC

New version uploaded to opencpn_2.5.1026_setup.exe - 4shared.com - online file sharing and storage - download

Hello,

I tried several times to charge the 250-1026 version by clicking on the link of the post. But nothing happens. After a while, I have a blank page.

Best regards

Gilletarom

[PjotrC]

I think 4shared.com - free file sharing and storage have a bad day, since their home page is not really functioning either... they will be back...