Forums > Windsurfing   Gps and Speed talk

GPS Regatta Time Window Filtering Software

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Created by berowne 1 month ago, 22 Oct 2025
berowne
NSW, 1522 posts
22 Oct 2025 9:59PM
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G'day guru'sLong time reader, first time poster (in this forum on track data anyway!).

berowne
NSW, 1522 posts
22 Oct 2025 10:01PM
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WNSW recently hosted a GPS session on Saturday up at Jimmy's Beach.

But, there are no good tools to do what we want for the GPS track analysis. I looked at GPS Speed Reader, GPS Stats Pro, KA72, and a few others. In the end I built my own. In an hour. Using "Windsurf" the best way to 'vibe-code' of course!


The first cut was looking OK...



But then when I applied the time filters, Mobz cracked 50 knots! 59.92 to be imprecise!

I know I did about 24kts during the time window, and did see Mobz cruise past me (when I was stationary), but not at 100km/h!




If anyone knows a good way to apply the kind of data filters GPSTC/KA72 use, let me know.

Or better yet, edit the github repo codebase


github dot com / Berowne / gps-tools

Cheers

Berowne

tbwonder
NSW, 730 posts
22 Oct 2025 10:56PM
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I haven't had a chance to look at your code.
But when extracting data for speed, make sure you are reading the Doppler measured speed not the positional speed.

berowne
NSW, 1522 posts
23 Oct 2025 8:15AM
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tbwonder said..

I haven't had a chance to look at your code.
But when extracting data for speed, make sure you are reading the Doppler measured speed not the positional speed.


"Read the code." that is so 2024. Actually to be frank, I didn't read it either. Well not really. I did notice a lot of time and distance algebra especially in the alpha calc function.
I'd be more than happy to work on this with other experts.
Also, I suspect the KML files only have position data which is fine for the KA72 maps and colour coded tracks, but not for the actual speed calculations.



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"GPS Regatta Time Window Filtering Software" started by berowne