Imperial to metric conversion problem into rain values

[Javier Oliver - EA5ZF]

Hi all.
The first thing I want is to apologize if you find any errors on my message. I must explain that I write in
Spanish and then I translate it into English.
The problem I wanted to comment on the forum is about the use of the metric system in the wview. I use a station
Davis Vantage Vue and I have observed many times that while rain upon data collected
correctly and stored in the main database correctly, is not stored with sufficient precision
(number of decimal places) in other databases, which by recalculating each day rain fails
precision to make the conversion.
For example:
0.2 mm rain is stored in the database file wview-inch correctly converted to:
"0.007874" which again is 0'2mm metric
But into wview-Hilow is stored:
"0008" gone metric that gives us 0'2032
If we look now another rain 0'4mm values ​​as found in 0016 has been stored Hilow we
would become a metric value of 0.4064mm which rounding to 2 decimal 0.41mm give us, then it is
see the error, and gives us one hundredth of a difference.
This means that when the rain is bigger, bigger can be the conversion error that accumulates
to rain and the annual daily.
I think the error is caused because the data stored in the database only used 3 decimals and this
precision error because going from metric-imperial-metric
Xavi

[Jörg Sommrey]

Hi Xavi,

hablo un poco el español. Si no me entiendes, podríamos conversar en
español - en email particular.

I've never put any attention to rain values stored in the hilow
database. Now that you mention this issue, I see exactly the same
behavior here. Indeed, this looks like a conversion/rounding problem.
I've done some investigation on conversion and rounding of rain data
before and I'd be glad to track down this one.

-jo



On Sun Feb 17 17:40:07 2013, Javier Oliver - EA5ZF

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[Javier Oliver - EA5ZF]

Jo, thanks for your reply.
I will do not pay attention to the data stored in the database Hilow were it not appear in the monthly summaries in the data sheet and NOAA data daily, weekly, monthly and yearly. That is, except in the archive database appear everywhere.
I watched a little to see if I could find where the problem is and think that originates when writing data Hilow, where there is an Update command where data are recorded with only 3 decimal digits.
But the problem is that you then have to compile your wview to correct it, and I do not know data is lost in the process.
The behavior exposed are observed in some stations here in Spain, but i think never has been corrected in any forum until now.
Clearly is a rounding problem at time to make conversion metric - imperial - metric

[Jörg Sommrey]

Hi Xavi,

this is really tricky and I'm almost desperate. Looking at my hilow
tables I realized that I had correct rain values until November 2012.
And I can't remember or even see in my backup logs what changed at
that time. The number of digits after point in the hilow table seem
to be the cause of the data loss.
My cumulative rain still looks sane, but I modified wview a long time
ago to use one more digit in the archive table.

Looks like we need Mark's help here.

-jo

On Sun Feb 17 21:31:16 2013, Javier Oliver - EA5ZF

[Jörg Sommrey]

On Sun Feb 17 21:47:10 2013, Jörg Sommrey <jo...@sommrey.de> wrote:

> Hi Xavi,
>
> this is really tricky and I'm almost desperate. Looking at my hilow
> tables I realized that I had correct rain values until November
> 2012. And I can't remember or even see in my backup logs what
> changed at that time. The number of digits after point in the hilow
> table seem to be the cause of the data loss.
> My cumulative rain still looks sane, but I modified wview a long
> time ago to use one more digit in the archive table.

I found something on my side: an erroneous rain calibration. This
means your problem is something completely different.
There's one place in wview where rain values in inches are rounded to
one decimal place. In my installation I've changed this to two places
long ago. Maybe you are hit by this rounding.

[Javier Oliver - EA5ZF]

Still waiting here for help on a solution to the rounding problem whime converting imperial to metric.
I hope it can be corrected in the next version of wview.
Not all the people are using imperial readings in the web, Central EU citicens still using metric values.

[SP1LOP]

W dniu niedziela, 3 marca 2013 16:53:06 UTC+1 użytkownik Javier Oliver - EA5ZF napisał:

Still waiting here for help on a solution to the rounding problem whime converting imperial to metric.
I hope it can be corrected in the next version of wview.
Not all the people are using imperial readings in the web, Central EU citicens still using metric values.

 Hi
For me, running a version of numeric and U.S. parallel
I have a whole page translated into Polish ...
http://www.sr8bbs.ampr.org/weather/Current.htm

Discover and a hint what and how to set