Expedition Navigation Software 
1 - ZeeZee
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Offline - Registered: 3/30/2016
- Posts: 321
Predicted TWS and TWD
Great to see Predicted TWS and TWD being added as channels in 10.8.17 !!
Are these channels the data for TWS/TWD coming directly from the grib's so are in fact Predicted GWS / GWD?
Would love to see a channel for Predicted MSLP being added as well!
- Nick
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- Registered: 9/16/2015
- Posts: 2,965
Re: Predicted TWS and TWD
Yes, from the grib data.
MSLP is easily done ...
- sparky
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- From: Cambridge UK
- Registered: 4/27/2018
- Posts: 245
Re: Predicted TWS and TWD
Could you also add delta channels for this data?
Like the dSogBsp channel but for observes vs GRIB data?
- ZeeZee
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- Posts: 321
Re: Predicted TWS and TWD
Tnx Nick, adding Predicted MSLP would be appreciated!
@Sparky: I have created a stripchart showing four channels: PredTWD - GWD - Pred TWS - GWS
Now it's easy to see the delta and correlation.
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Thread Starter- ZeeZee
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Re: Predicted TWS and TWD
Talking about stripchart:
Plotting Peditected TWD and GWD into a single "strip" is a nice option that Expedition allows you to do (by adding PredTWD as channel2 data and then plot GWD as the main channel data). This will easily show you the delta between the two in a single graph overlay.
@Nick: what would be a very useful addition here is to also show the average and SD for channel2 when you set wands. Now it's only shown for the main channel data. This would allow to see the delta between the 2 channels (now you need to create a separate 'strip' to get this data and you loose the graphical feedback as the channels are not overlaid anymore).
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Thread Starter- Nick
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Re: Predicted TWS and TWD
Probably no delta, but there will be another solution for that when I find time to finish it. We can have too many channels.
That might get too cluttered?
- ZeeZee
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- Posts: 321
Re: Predicted TWS and TWD
For me a delta channel for PredTWS/TWD would not be needed as this is a longer term data items that can perfectly be analysed via Stripchart. However, having the AVG and SD for channel2 would be a big plus (mabe just add it between brackets behind the AVG/SD of the main channel.
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Thread Starter- nav
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- Registered: 12/20/2015
- Posts: 91
Re: Predicted TWS and TWD
ZeeZee wrote:
Talking about stripchart:
@Nick: what would be a very useful addition here is to also show the average and SD for channel2 when you set wands. Now it's only shown for the main channel data. This would allow to see the delta between the 2 channels (now you need to create a separate 'strip' to get this data and you loose the graphical feedback as the channels are not overlaid anymore).
100% agree!!
- Boj
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- From: Netherlands
- Registered: 10/02/2016
- Posts: 38
Re: Predicted TWS and TWD
Very nice new feature! (PredTWS). Is it scaled down for 10m or is it at Mast Head? While typing this I must admit that I do not know; TWS is it at MH or corrected to represent 10m? I always assumed it was at MH.
I come to this I've recently used different polars and had to correct them for MH. Would it be an option to have a tick at the polar box to select whether you use a 10m or MH polar?
And second; would it be an option in the Weather settings to select mast hight instead of scale 10m winds. (have Exp do the correction formula for you and so be able to use 'scale 10m winds' to correct your GIRB to what you are actually measuring)
Thanks for all the work and thanks for the upgrade!
Last edited by Boj (7/27/2018 6:37 am)
- ZeeZee
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- Posts: 321
Re: Predicted TWS and TWD
@Boj
Afaik the grib's are always at 10m. But you are right, in order to make the PredTWS comparable to the GWS the PredTWS should be corrected with the scaling percentage for mast height as you have entered into Exp. @Nick: can this be considered?
I don't think you want the formula to calculate the mast height correction as part of Exp. There is no general agreement on the exact formula to use, so just entering a percentage into Exp gives you all freedom.
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Thread Starter