Integration with QtVlm - Data files and Import/Export

[maitai]

You're right, there is no need to trim the sails or even to choose the proper sail. You are the navigator, just that.

The next very big race is planned in November, round the globe and starts in Vendee, France . To get use with all that you can train on a permanent race, for instance a good one is Brehat->Horn->Locmariaquer in the fastest boat in the world (BP5). You are not obliged to finish anyway... and you start when you want on such a race.

Races annoucements and instructions are at La Taverne, in English and French.

This is not real sailing of course, and it doesn't claim to be. But it's a good way to train on wheather planning and routing decisions during the winter...

[rgleason]

Maitai, I must confess, I need to get better with QtVlm first. To that end, I am having difficulty understanding how "Routes" work.

"Routings" are quite clear, we can pick from the boat or from a POI or Mark and then to a certain POI or Mark, then the program does a wonderful job of figuring out the optimal route using the current grib file and boat polar selected.

For the life of me, I cannot figure out what determines which mark(s) a "Routes" is going to use. Furthermore some of them are empty in the second tab. I try to figure out how to get them to fill up with some series of boat movements and I am unable to make them work. "Routes" are certainly powerful because they give us a full listing of the TWA, TWS, locations, etc. but I am unable to control what marks they are using. How is this done?

Perhaps with that information, I will be able to understand the difference between a "Routing" and "Routes". But maybe you could explain that again to me?

Thanks.

[rgleason]

PS. I also wonder how I can string together multiple "Routings". For example I can put in a series of Marks or POI with Alphanumberic or Numeric suffices in order, and then by selecting the proper beginning and ending have the optimal route run for each LEG. How am I able to string together LEGS into an entire "Voyage" (to avoid confusing terms) or is that something we do by hand?

[rgleason]

I think I understand it now.
1. Create a "Routes" named Route-1
2. Create two or three Marks named (Mark-1, Mark-2, etc) by right click on the location and "create poi" then select "mark" from the dropdown.
3. Edit each mark in succession (right click - edit) and select Route-1 from the route dropdown. Then select the "Sequence Number" for the Mark.
4. An Optimized Route will appear without the isochrone which has been calculated in the background.

[rgleason]

Would it be possible to select the "Poi" or "Marks" from within the particular "Routes"? It might be more natural to everyone, since Routings allows the same process. Just let us line up each Mark or POI successively?

[maitai]

I am not sure I completely understand the question or problem.

A route is an ordered list of points. It can starts from the boat or from a another point. The order of the points can be either by sequence number, or by alphabetical order. You can assign POIs to a route (or Mark, or Beacon, doesn't matter).

So let's assume you want to create a route manually.

You go Route->Create a route and just click ok, leaving all options by default. Nothing appears, which is quite normal since so far there is no points in your route. Then you create a new POI, or edit an existing one, and assign it to the newly created route (you can also perform this with right-click on the POI). Now a ligne appears between your boat and the POI, and the POI shows at what time you will arrive. If you move the POI (or the boat) by shift-left-click/drag mouse, you see the line moving and the eta changing. The line is not always straight, because qtVlm calculates that you need to tack or gybe because otherwise you wiill be to much upwind (or downwind). It uses by default BVMG algorithm (see some posts before for an explanation). You can change this by right-clicking on the POI and select another navigation mode. For instance select Ortho, and you will see that the line is always straight now (well, as straight as Ortho is on a flat map ). You can insert more POI to the route, either inserting a new one or editing an existing one. Since you have left the route's option by default, the name of the newly inserted POI is used to determine it's order. Let's say that your first POI was called POI-10, then if the new one is called POI-20 route will first go to POI-10 and then to POI-20. And so on...

Route does not calculates the best, optimized way to go to a point (well, there is an optimisation option but it's not like a real routing). It just go there the best way it can and calculates how many times you must tack/gybe and your ETA. Just like you would do IRL, you want to go to that point in your North, you head towards it and if the wind is full in you nose you start a tacking session.

Routing does another job, which is to calculate the best way to go to that point in your North (maybe it's better to go East first and only after a while to go West). Then you can convert the routing in a route and the route issued from the routing just behave like the one you created manually (i.e. you can insert more points, remove some, change the navigation mode, simplify it, optimize it, etc).

[rgleason]

Yes, your description of how to use "Routes"-"Create Route" or "Edit Route" is better than mine, and that is the way I understand it to work.

Route does not calculates the best, optimized way to go to a point (well, there is an optimisation option but it's not like a real routing). It just go there the best way it can and calculates how many times you must tack/gybe and your ETA. Just like you would do IRL, you want to go to that point in your North, you head towards it and if the wind is full in you nose you start a tacking session.

I did not realize that Route(s) does not do a full optimization. This may be dumb but what is IRL?

An idea for Route- An additional way of adding Marks, POI or Beacons to a Route might be from within the Route, so that there is a button to add a mark(s) in a sequence, for example. Or maybe there is a third tab for the mark sequence only, where marks can be added, highlighted and deleted, or moved, etc. Without depending on setting the Marks "route" and sequence number, or alphanumeric or numeric.

Then you can convert the routing in a route and the route issued from the routing just behave like the one you created manually (i.e. you can insert more points, remove some, change the navigation mode, simplify it, optimize it, etc).

Okay, let me see if I understand. The "Route" can be changed by inserting points, remove points & simplified to be like the Optimized "Routing" for that leg. You can adapt the marks to skew the leg to respond to how you may think the "actual" weather patterns will work (...the next grib update). Is that correct?

Question about "Route" - Is the optimization limited to a more "local" level or smaller window, rather than the full grib? If so, how big is that window? I now re-read that "...uses by default BVMG algorithm (see some posts before for an explanation)" which is Best Velocity Made Good. Your definition here -I'm going to have to think about this.

In VLM there are 5 navigation mode:

-Heading: you just enter a heading and the boat will go that way. Loxodromic route, in fact.
-Wind Angle: the boat will sail at a fix TWA
-Orthodromic toward a WP: the boat will follow an orthodromic route to reach a WP
-VMG: the boat will follow the best VMG route towards a WP according to polar, grib and a WP.
-VBVMG: (stands for VeryBestVMG) The boat will follow an orthodromic route towards a WP, unless the WP heading is not inside the best-VMG winds according to polar and wind (i.e. it will go ortho unless for instance ortho will make it sailing to much upwind)

Thanks for your help and explanation.

[maitai]

IRL stands for In Real Life.

As for the route versus routing:

You have to see the route as a calculation of how much time it will take to go from A to B as directly as possible. It will not go completely straightly only if it would mean too much upwind (or downwind), unless the nav mode is Ortho. That's all it does, but it's already a lot since it will analyse wind and current every 5mn all the way from A to B to calculate this. Btw if the route would be able to find the best way from A to B then what would be the use of Routing There is an optimization function in the Route module, so I agree it's confusing. Let's leave it aside for the time being.

Okay, let me see if I understand. The "Route" can be changed by inserting points, remove points & simplified to be like the Optimized "Routing" for that leg. You can adapt the marks to skew the leg to respond to how you may think the "actual" weather patterns will work (...the next grib update). Is that correct?

I don't think I understand the question. You make a routing, you convert it to a route, you get a route full of points (one per iso-step). You can simplify it with route->simplify. Then it's you decision to follow this route, or to change it a bit by adding/removing/moving points.

Question about "Route" - Is the optimization limited to a more "local" level or smaller window, rather than the full grib? If so, how big is that window? I now re-read that "...uses by default BVMG algorithm (see some posts before for an explanation)" which is Best Velocity Made Good. Your definition here -I'm going to have to think about this.

The route optimization process uses the full grib. As I have said in another post this process is more intended for Virtual Sailing than for Real Sailing. Basically when a route is issued from a routing you have a point every hour (say). It make sense to see if a better result would be achieved if you study intermediate positions. This is anyway a bit too much IRL (=in real life ), since the grib unfortunately does not represent reality accurately enough.

The routing uses only visible grib unless you unflag this option when you create it. That's also why there is an auto-zoom function before the routing starts that you can uncheck. The routing module does not "see" coasts outside the screen, so removing these options might end up with a nice optimized route... for a car

The route uses by default VBVMG navigation mode by default.

[rgleason]

Ok, I've created two versions with basically the same legs:
1. Route (yellow) named RouteA -Legs between Boat, Poi1, Poi2 & Poi3 using command "Route" in yellow
2. Routing (orange) -3 Routings. Route-A with Mark-A to Mark-B, starting "Now" using command "Routing" in Orange. Then Routing-B with Mark-B to Mark-C with a time set to be sequential. Then Routing-C with Mark-C to Mark-D with a time set to be sequential.

Its pretty clear that the three "Routing" -orange create a different and more optimized path (VBVMG) than a "Route" -yellow. What does the "Route" use for creating the path?

Note that the Route -yellow "RouteA" window is opened on the second tab and it shows lots of detail about the various sailing segments that is not shown for a "Routing".

From what I understand from Maitai, we next must export the optimized Routing path (orange) and import it into a new Route to get the similar information for the optimized route.

[rgleason]

I tried to export the orange optimized first leg, "Routing-A" but could not find how to do that. I then created a series of Marques labeled 0 through 6 that approximated the orange optimized first leg and assigned them to a new Route called "Route-A-Transfer" which is show in purple.

Now when I go to Edit Route and select "Route-A-Transfer" then select the second tab for details, route detail that approximates the optimized route is shown.

I do not know if this is the way I am expected to use this tool. I would think there would be some ways to export and import.

[rgleason]

Also when it drawing along isochrones alternative routings, and you right click, it says "Create a pivot point" and "Create a pivot point changing route options" what are those for?

-Create a pivot point, adds a new routing along that path. Does it remove the old routing?

-Create a pivot point changing route options" seems to bring up a new Routing dialogue and then redraw the isochrones and create a new routing eliminating the old ones.

[rgleason]

I am unable to get back those orange Routing-A from MarqueA to MarqueB
and Routing-B from MarqueB to MarqueC.

[maitai]

Edit the routage, and choose "Convert to a route". It's a checkbox on the right side

[rgleason]

Ah, in Routing-A it was right there. Converted to a Route and then Edited the route and selected the checkbox "optimize" and there was no improvement in time, then selected "simplify" and it reduced the number of waypoints with no change in arrival time. -That was easier! Thank you.

[rgleason]

What is "Draw a Grib Esteem"? It comes up when you right click any location. It seems to have
Says TWA Tool at the top
Part 1-5 tabs
True Wind Angle, Heading
nb Cranks (what is that?)
Store: Poi or Reckoning
Start Date: Grib or Vac

Thanks