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[LUG]Re: tide data pointless proc. - get highest-grf / lowest-grf

 

Maybe best to know what your data-processing criteria are?

One I could add is
- to an approximation the tide changes 6m in 6hrs
- so that’s 0.25m in 15mins
- leave at that as you are searching around the “turning-points” - slow changes
- add a bit for real effects of wind changing, etc.
- so could throw-out data-points where more than 0.4m change in 15mins
Reason I put “broadly it’s there”.  Must inspect data for improbable-and-isolated 
data points.  Then arrive at what I am going to plot and declare that, to the best 
of ability, according to declared criteria “this is it”.

I have once heard “… and we can see what it is that you have computed”.
Massively tipped things in my favour, leaving a feeling of certainty about what they 
were looking at.

These tools would surely be very useful to look for trends which if seen you 
investigate.
Mindful of “Texas sharpshooting” !  :-)

Thanks,
Rich Smith  


> On 24 Apr 2023, at 13:56, Tom via list <list@xxxxxxxxxxxxx> wrote:
> 
> Perhaps moving up to AI might help. Theres a free app called Weka which comes with 
> free online courses and also an app called Moa which can eat time line data and 
> process it as it arrives. I did a course a few years ago and remember it had 
> mechanisms for handling date with time based cycles  and all sorts of goodies for 
> finding and marking outliers and removing them from datasets..
> I think you'll find high tides will break records regularly from now on - low 
> tides breaking records probably means a tsunami is on the way!
> Cheers cheerily
> Tom te tom te tom
> On 24/04/2023 07:41, rds_met wrote:
>> Hello all
>> 
>> I had a bit of complete relaxation time yesterday and thoughts
>> flowed...
>> 
>> I saw you could do the lot with "awk" - the unix toolkit awk command /
>> utility.
>> 
>> "Rough" first output.
>> http://weldsmith.co.uk/temp/tide_n22_hi_lo_all.png
>> 
>> Broadly "it's there"; however there are problems where the tide gauge
>> was mulfunctioning (a tide making 11.something m above Lowest
>> Astronomical Tide would if it really happened make the news!!!).
>> Etc.
>> 
>> The horizontal axis is the tide-gauge's sequential 15-minute
>> data-record increments in a year
>> (* 365 24 4) ;; 35040
>> 
>> I would help a more sophisticated "data-crawling" program if there
>> were inclination to make one.
>> 
>> Regards,
>> Rich Smith
>> 
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