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Author Topic: Strange rain measurment  (Read 1821 times)

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Offline Downlinerz2

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Strange rain measurment
« on: February 09, 2009, 08:56:01 PM »
Hi to All,
  I have a question just out of curiosity.  I am not sure if the problem is from VWS or my OS WMR 968.  I was checking some data from last year and I found a rain measurement of 0.31". I know that my station measures rain at 0.04 inch so I am curious as to how I have a total for the day of 0.31"?  :?: I am assuming it is a bug in the VWS.  Has this happened to anyone before?  I just want to know out of curiosity.  Thanks for all your help. =D>
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Offline sam2004gp

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Re: Strange rain measurment
« Reply #1 on: February 10, 2009, 12:04:00 PM »
It is number rounding by VWS, it does not record an actual .04 on each bucket tip, but something like .0385 (not sure on the exact number).  But the VWS displays rounds that up to .04  Eventually these "rounding errors" catch up so when you multiply the actual number of .0385 x 8 Bucket tips you get  .308.  Then VWS rounds that number as well and you end up with .31.  So we all see it, if you change the precision of the Broadcast.jpg to more places you will see the actual number but then who wants to look at rain number to 8 places.
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SAM --->>> http://www.mountcrawfordweather.org
OS WMR-968 with a Dedicated PWS Weather Computer running VWS v13.01 p09

Offline Downlinerz2

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Re: Strange rain measurment
« Reply #2 on: February 10, 2009, 12:08:30 PM »
Sam,
   That makes sense! Thank you for answering.  It just kept bugging me and I could not think of anything that made sense in my mind.  Thanks again!   =D> =D>
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Offline sam2004gp

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Re: Strange rain measurment
« Reply #3 on: February 10, 2009, 12:24:23 PM »
No problem.  I also see the same type of error on my webpage when I get two consectuive days of rain.  The sum of Day 1 and Day 2 added together don't match the number that was added to my month total sometimes.
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OS WMR-968 with a Dedicated PWS Weather Computer running VWS v13.01 p09

Offline SlowModem

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Re: Strange rain measurment
« Reply #4 on: February 10, 2009, 12:27:50 PM »
Quote from: sam2004gp on February 10, 2009, 12:24:23 PM
No problem.  I also see the same type of error on my webpage when I get two consectuive days of rain.  The sum of Day 1 and Day 2 added together don't match the number that was added to my month total sometimes.

must be that new math thing
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Greg Whitehead
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Offline Downlinerz2

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Re: Strange rain measurment
« Reply #5 on: February 10, 2009, 01:17:31 PM »
  I was almost afraid to post the question!  I thought I would get 10 answers teaching me how to multiply again.  I kept doing it over and over in my head making sure that 7 x .04 wasn't 0.31 :oops: :oops:!  I almost got the calculator out to check myself but I was able to restrain myself.  But I am glad I asked.  Learning something new is never a bad thing, well, almost never. I won't hesitate to ask in the future.  Thanks again!!! Anyway thats enough math for today!! :!: ](*,)
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Offline Anthony

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Re: Strange rain measurment
« Reply #6 on: February 10, 2009, 03:43:52 PM »
I've noticed this my self of several ocassions. Just always blew it of as a VWS sort of thing. But thanks for the explanation.

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Thanks,
Anthony
WB8YUE
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