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User Manual / Evaluating results


There are many different ways to evaluate the results produced by the weather router solver. All of the various evaluation methods were first presented in the Getting Started / Evaluating the results page.

You can choose what the system will draw by turning on or off the various properties in the Draw section.

Draw area options.

Isochrones. Good for progress.
Segments. Good for flow.

You have control over how to view the isochrones and paths.

If you turn both isochrone options off, the isochrones are not shown at all. The different Draw options are:

The cursor fleet - examining the solvers decisions.

Max wind failures
Min wind failures
Motoring

Using the cursor fleet you can see which headings, radiating out from each isochrone point, the solver considered as it progressed, building the isochrones one after another. Yellow lines indicate that a heading violated the upwind sailing angle limit. Orange lines indicate violations of the downwind sailing angle limit.

Looking at the middle image, some of the headings the solver considered at the given point violated the upwind sailing angle limit (they were heading too close to the wind.) Some of the headings violate the downwind limit, sailing too far downwind, and some of the headings resulted in their being less wind that was allowed. (In this case, the minimum wind was set to 5 knots apparent.)

When the isochrone images are surprising you in some regard, viewing the cursor fleet in those areas can often lead to understanding what is going on.

Analysis images.

The Image popup allows you to select from many different types of images. Samples of each of these are shown below. Click on any image to see a larger version.

No image shown.
GRIB file content shown.
True wind speed (TWS).
Apparent wind speed (AWS).
Upwind / downwind true (TWA).
Upwind / downwind apparent (AWA).
Wind on port or starboard.
Vessel speed through water (STW).
Current speed (drift).
Sailing or motoring.
Day or night.

The images show the indicated condition, through time, and across the full set of isochrones (the solution space.) You can think of these images as somewhat analogous to a meteogram, which shows weather conditions, through time, at a point.

There are a few points which may be helpful:

There is one more point that should be highlighted with respect to the GRIB file image. It is possible for the solver to generate solutions for many different types of wind fields, for example using ensemble models or the NBM Oceanic probability wind fields. When you select one of the solution paths, perhaps by clicking on it, the GRIB display is modified so that the wind field shown is the one associated with the selected solution. For example, if you have five paths generated, one for each of the NBM probability wind fields, selecting the different paths will adjust the GRIB display.

Solution table

If you have read through the Uncertainty section in the introduction, you may recall that this weather router is able to generate many variations for the solutions.

The solution table allows you to manage the complexity when dealing with these many solutions.

There are several things to note with respect to this table:

Solution details.

You are able to see a detailed report on the selected solution path by clicking on the Solution Detail button.

Do you want to see a sample report? Click here.

Note that the solution details report has its own set of settings, where you have control over some of the fields which are shown, and how they are presented.

Meteogram

You can view the weather route as a meteogram of values across its length. This is accessed by clicking on the button in the top right corner of the weather routing text information group:

When you do that, you will see something like the sample shown below:

(Click above for larger version.)

Note that the first row, where the vessels speed through water is shown is a little unusual. The speed is shown as a stairstep graph, rather than a smooth curve. This correctly reflects what the isochrone algorithm is doing. The boat speed is determined at the start of each isochrone and then held constant until finishing that isochrones time interval. This is followed by the wind being evaluated at the new location and next isochrone time, which in turn, determines the speed for the following interval.


LuckGrib Weather Routing is currently only available on macOS. Support for iOS and iPadOS is under development.