OpenCPN Route Planning with Time and Tide

[PjotrC]

I tweaked the Route Properties dialog into a prototype Passage Plan. I aimed at minimizing the growth of user interface, while hopefully providing useful info.

In return for providing a fixed Departure Date the user obtains now for route waypoints along the way:

- specific ETA at each WP
- altitude of Sun (day, twilight, night, sunrise, sunset)
- state of tide

Time display/entry can be selected between UT, current timezone of the PC, or Local Mean Time of target waypoints (for advance planning those remote passages).

Tide display has two modes:

- if a Tide Curve Window is open on screen, tide data for this station (the most recently opened one) will be tabulated at all Route WPs
- otherwise, if WP name contains a name of a tide station, data for this station only will appear at this WP ETA

I plan to resolve the selection between identical names for different stations just by choosing the most nearby one.

Todo :

- allow different plan speed for each leg
- include a polar speed diagram and GRIB forecast into the plan
- include the currents data as well...
- ...

Piotr

[ktcanuck]

This looks very useful. Do you enter cruising hours per day? For someone simply using Windows 7 is there (going to be) a way to import your mods as a patch or does this all have to be compiled under Linux etc?

[PjotrC]

I started thinking about making a route-based Voyage Plan, i.e. planning for extended stopover times, but it seems that this is not necessary. It should be sufficient to stay with one route -> one passage.

In a couple of days I will stop testing and post the patch to flyspray.

I build under Windows only, but this should be portable to other platforms as well.

[fgd3]

Originally Posted by PjotrC

In return for providing a fixed Departure Date the user obtains now for route waypoints along the way:

- specific ETA at each WP
- altitude of Sun (day, twilight, night, sunrise, sunset)
- state of tide

Time display/entry can be selected between UT, current timezone of the PC, or Local Mean Time of target waypoints (for advance planning those remote passages).

Neat idea. I'll be looking forward to trying it out when it is incorporated into a beta version.

Originally Posted by PjotrC

Todo :

- allow different plan speed for each leg
- include a polar speed diagram and GRIB forecast into the plan
- include the currents data as well...
- ...

Piotr

That will be very nice when you get it working.

Fabbian

[jonasaberg]

Originally Posted by PjotrC

Todo :

- include a polar speed diagram and GRIB forecast into the plan

Piotr

I think there was a post about weather routing earlier (much earlier) where someone had programmed it into a webapp or application... I am pretty sure the author volunteered to release the code on request. Need some digging into old posts...
Maybe this could be a good starting point for this very useful addition for distance sailing.
In my experience weather routing works well for sailing in (good) prognosticated weather over distances longer than a couple of tens of NM.

/Jonas

[PjotrC]

I posted the patch for basic route planning to flyspray feature requests.

Below is an example of the selective interface to tide tabulation, and specification of stopover at a route waypoint.

Enjoy,

Piotr

[idpnd]

Nice Piotr.. and perfect for my upcoming Brittany cruise

[jonasaberg]

Weather routing links:
Weather routing
Describes the principle quite well

Sailing Simulator: Home
A fast implementation of WR.

Unfortunately not open source...

/J

[idpnd]

Yes I chatted to zezo dude back in the day, he sort of said he might contribute code to a real life WR solution - you can check on the zezo.org forums

[jonasaberg]

ok, I was sure I read something somewhere. Your post explains that

Maybe it would be best if Pjotr or someone up for the coding took the contact...

Weather routing in CPN would be seriously cool.

/Jonas

[antxon]

Beautiful job, Piotr!! I hope at last we will have a date of arrival for each wp and for the whole route! Something apparently essential for a navigation software that people sailing on many days ocean passages were really missing. Thank you for your work and initiative.

[Gilletarom]

Hello PiotrjC

With version 2.5.11.28.

Install : Ok. It seem that it run well ... but ....

The wind direction arrows change when moving a WP! And as for the curves of equal pressure.

Best regards

Gilletarom.

[PjotrC]

Originally Posted by Gilletarom

The wind direction arrows change when moving a WP! And as for the curves of equal pressure.

Gilletarom...

This is intended behaviour... when you start dragging a waypoint, the GRIB display synchronizes with the ETA for the starting time of the leg affected. When you stop dragging, the GRIB shows the state as of the ETA of the end of the leg.

In this way you see on screen what should be seen when planning this leg. Of course this is best guess - the nearest GRIB record in the set. If you adjust the waypoints in the natural order - from start to finish of the route, then the barbs (maybe) change only at the end of dragging.

This can be switched off in the GRIB Control Dialog by ticking off "Sync with Route", but then the display is less meaningful... it just shows some point in time...

It gets a little more complicated with Wind&Sea Current together - some GRIBs give wind data every 6 hours and Currents - every hour. I give preference to sailing - so if the Polar is not "none", the display shows only the screens with wind included, but computation behind the scenes takes the best Current prediction available. If the Current is preferred - just set Polar to "none".

Thanks for trying...
Piotr

[Gilletarom]

Whaooooo !

Better and better!

[PjotrC]

Best of all, by selecting:

- "Polar Selection" = none
- "Sync to Route" = Off
- "Include Drift in VMG" = Off

one gets good old 2.5.0 behaviour, just with tabular presentation of forecast...

Wind data is used if within 24 hrs from timestamp.
Sea current data is used if within 1.5 hrs from timestamp.

P.