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9/23/2019 10:06 pm  #11

Re: How does Model Accuracy actually work?

I meant that MA can probably calculate GWD/GWS themselves based on the Expedition TWD/TWS + Current data fom the existing log file format.

Last edited by ZeeZee (9/23/2019 10:06 pm)


9/24/2019 5:48 am  #12

Re: How does Model Accuracy actually work?

It compares the wind logged at any particular time with what the different models forecast for that location/time, and analyses the results statistically.

:::Campbell Field::::::www.fieldyachting.com:::

9/29/2019 1:29 pm  #13

Re: How does Model Accuracy actually work?

ZeeZee wrote:

Thanks for the response.
I'm with JL:   using GWD and GWS instead of TWD and TWS is essential for Model Accuracy to be useful in areas with currents. 
GWD/GWS are not recorded in the Expedition log files,  but all the data you need to calculate them is there: Set, Drift (I think Leeway is already taken care for in the TWS/TWD of Expedition?).   I'm sure Nick can help you which formulas to use in order to make sure they match up with how Expedition makes these calculations.

Great animation video to show the benefits of MA!!

This is a balance of priorities for Model Accuracy in our development, just as a navigator has to prioritize which GRIB file source to trust the most!

In regards to Ground Wind vs TWD/TWS, we are talking very minor differences in analysis output. 
To be honest, in my entire sailing career, to include Barn Door TransPac wins, Volvo Ocean Race training, ect... I have never heard of Ground Wind until this forum. I am not discounting the point at all, but I think it may show the context of the value of discussing it at too much length. 

There are so many instrument calibrations that are critical to to capturing proper wind data, and a Boatspeed calibration is critical as well, particular for a correct set/drift output. We have all sailed many boats and are very familiar with the poor quality of BSP cals installed on some boats. To create another layer of data conversion now totally dependent on the BSP cal being perfect I dont think is the best use of effort and time right now for our software application.

That would be like debating final 1% of a solution where we have already completed the first 99% of the solution, which didn't even exist until Model Accuracy came about.. 

We can tell the user which forecast is the best, and why. We can help identify time offset trends, and trend errors with recommendation calibrations. 

At the end of the day our mission is to support the navigator by helping them understand which GRIB file is the best and why. The simplicity of the user interface is critical to that process, making it as easy as possible to choose which grib file to trust the most. 

We will certainly get to the GW data collection for sure, but we have a few other items first on the docket. We want to capture NMEA data from all Race Committee Boats, race marks with wind instruments, and coach boat instruments for analysis as well.  Once we capture that interface we will be in great shape to come back and discuss GW capability. 

All the best guys and thanks for your input! We hope you download Model Accuracy and give it a try!

     Thread Starter

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