strange weather routing

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strange weather routing

Postby kimis » Fri May 04, 2012 3:33 pm

have noticed strange weather routing.
I often have situations when it sugests very sharp TWA, lets say 8 degrees now. what is also strange, if to measure with measure tool distance between 1h isochrones, measuring tool says that suggested 1h track segment would be covered in 2, 5 or even 7 hours, what is more real with such TWA.
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Re: strange weather routing

Postby omar » Mon May 07, 2012 11:24 am

This low TWA is probably caused by poor configuration.
Vrtool WR has a many parameters, to allow flexibility in all possible situations and scales.
But this also gives ample opportunities to screw up.

For VORG I'm using the following parameters:

Interval= 1 (or 0.5)
Up to isochrone=144 (make sure the correspondent wind forecasts are loaded)
# of branches=43
max angle to destination=120
show isochrones=6h
wake angle=35
Iso point spacing=1.5 (%)
[x] Collision detection (checked)
[x] Add branches at isochrones (checked)
[ ] Add branches at full degrees (unchecked)

(I'm using the polars database provided with version 2.0)

Note that using long term forecasts (like 144h) can be deceiving.
Short term forecasts are more reliable than long term ones.
So I reset the "Up to isochrone" parameter to a smaller number
(say 36 or 48) and perform another calculation.
If both routes (short and long term) point to the same direction, one can be confident.
If they differ a lot, the situation requires a more detailed analysis.

Each isochrone set is marked with a time label (p.e. 12h, 24h)
This is the isochrone point closest to the WR destination.
You cannot connect these points, for they don't belong to the same route.
If you want to know the route that will take you to a certain isochrone
best point (for example 48h), set "Up to isochrone" parameter to 48 and recalc.
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