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Another rainfall question....

Discussion specific to Fine Offset and similar rebadged weather stations
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daj
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Another rainfall question....

Post by daj »

I've read all the posts on here regarding EasyWeather and the rainfall data problem, however I am not sure if my problem is connected so I have created a new topic.

I attach an image showing two graphs produced by Cumulus -- the top one would imply that there was rain from midnight until 2am. However the bottom graph shows no rain until 5:30am (and the top graphs shows no rain then).

Looking at the EasyWeather.dat file it suggests there has only bee 0.6mm rain since midnight, so how is the bottom graph being calculated? I attach an extract of the file in Excel format -- if you look at column U it shows the 0.6mm rains early on and nothing else.

what would cause this?

Thanks

David
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David
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daj
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Re: Another rainfall question....

Post by daj »

Ok, so I can not upload an Excel spreadsheet or a PDF, so here is a link to the file in both formats...


https://dl.getdropbox.com/u/33488/RainData.pdf

https://dl.getdropbox.com/u/33488/RainData.xls
David
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steve
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Re: Another rainfall question....

Post by steve »

Cumulus uses two values for rain from the easyweather.dat file, the rain in the last hour and the rain so far this year (columns V and Z in your spreadsheet). It uses the rain in the last hour directly as the current rain rate, and it uses the year to date figure to work out how much rain has fallen today (by remembering what that figure was at the start of the day).

So, given the above, there are clearly some strange things going on here. Firstly, Cumulus appears to be using column U for the rain rate and column V for the rain this year. Secondly, your figures for column V seem very high - but perhaps this is the 'Easyweather rainfall bug'.

Could you please send me your actual easyweather.dat file so I can see why Cumulus is apparently using the wrong figures? Please email to steve@sandaysoft.com

Thanks,
Steve
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daj
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Re: Another rainfall question....

Post by daj »

Thanks

Yes, based on my own visual observations of the rain fall column V is very high and seems amazing inaccurate but U seems right

I will email the Easyweather.DAT file
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Re: Another rainfall question....

Post by steve »

It's not clear from your easyweather.dat file where exactly Cumulus was getting those figures from.

I've noticed that Easyweather was downloading a lot of entries at about 09:34 - had you just started it running then? And did you have Cumulus running at the time it was doing this? I'm wondering if Cumulus was reading half completed entries while Easyweather was writing them. But in any case, if you're not running Easyweather and Cumulus 24 hours a day, Cumulus isn't going to be able to give sensible daily rainfall totals, because of the need for it to know the total at the start of day. I'm afraid it doesn't do anything clever with the easyweather.dat file, it just dumbly reads the last entry each time and takes that as a new set of data. I intend to make this all much better in Cumulus 2.

You do also seem to have the Easyweather rainfall problem.

The best I can suggest for now is:

1. Run Easyweather and Cumulus 24 hours a day, if you're not already.
2. Try to minimise the chances of Easyweather and Cumulus accessing the data file at the same time
3. Hope for a fix for the Easyweather rainfall problem.

I would consider changing my mind and trying to make this version of Cumulus talk directly to the station (and use the data from the data logger, so it didn't need to run 24 hours a day), but there's the added complication of the USB connection, so I'd have to add USB support as well, and that complicates things somewhat.

Steve
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Re: Another rainfall question....

Post by daj »

Thanks for the reply.

I can confirm that I run EasyWeather and Cumulus 24 hours per day -- I only sent todays extract as the live version has 32,000+ entries. I've only recently started using Cumulus on this data

On point 2, "minimise the chances of Easyweather and Cumulus accessing the data file at the same time" -- how do I do this? Is there a setting in either of the apps?
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Re: Another rainfall question....

Post by steve »

Any idea why Easyweather appeared to be doing a large download at about 09:34? If you look at the transfer times compared to the actual data times, most of the night's data appeared to get downloaded this morning? I'm not sure what would happen if Cumulus were to try to read the file while it's being written to.

To minimise the chance of both programs accessing the file at the same time, assuming you have them both set to the same interval, you could start Easyweather off, then wait a couple of minutes and start Cumulus.

Steve
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Re: Another rainfall question....

Post by daj »

I am going to try digging a bit deeper tonight to understand what is going on.

Question -- when Cumulus reads the DAT file periodically, is it only reading the last line of the file?
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Re: Another rainfall question....

Post by steve »

Yes, that's right. I did it in the simplest way possible - it just takes the last line in the file and processes it as if it had just received that data from the station.

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Re: Another rainfall question....

Post by daj »

I wonder if that is the problem then?

What I have noticed is that EasyWeather can be busy for a while and the status at the bottom tells you it is calculating rain data; when I saw this, it ran for 15 minutes and I only noticed it when it was 60% into this process.

If Cumulus is reading the last line only, then it could read it several times during that long period of calculation, therefore artificially aggregating data in Cumulus.

Could a solution be for you to store the sequence number (the first column in the row of the dat file) -- if you then re-read the last line and it has the same sequence number as the last processed one by Cumulus, it ignores it. Cumulus keeps checking until it gets a different sequence number. This could also stop errors in Cumulus if the EasyWeather software hangs.

Just shoot me if I am going down the wrong road here -- or interfering !
;)

David
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Re: Another rainfall question....

Post by GeniSim »

Hi,

This is a quite interesting discussion. I can tell you that it is not all EasyWeather versions that are taking a very long time to recompute the rain data. The version 1 that I am currently using http://www.lacrossetechnology.co.nz/ima ... WS1081.zip and the version 2 that is available on Fine Offset Electronics http://www.foshk.com/en/products/show.asp?id=41 are recomputing rate data quite fast compared to the version 2 that I got with my National Geographic 265NC station (that version has no link to Foshk web site in the About EasyWather panel).

Marc
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daj
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Re: Another rainfall question....

Post by daj »

Interesting that various versions of EasyWeather take time to calc the data, or not!

Last night my EasyWEather software shutdown, which is a first for me -- I think this then confirmed that Cumulus continues to read the DAT file, and as a result the data increments constantly with old figures. (the signs were that the Cumulus graph for temperature, pressure, etc were all flatlined (i.e. the same value over a long period))

I know Steve is working his magic on a possible solution so fingers crossed.

For my part, I wondered if I could write a routine to read directly from the USB and present this to Cumulus for calculation but I think there will be a slicker solution with Cumulus directly.
David
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Re: Another rainfall question....

Post by philcdav »

Hi guys. this 'rain bug' is a pain.

I had an issue with the reading beeing obviosly wrong so look at the data.

Sure enough, last week saw a duplicate block of about 200 entries added onto the file as new records. The giveaway was the date stamp. As this data contained 'lots of rain' it was added twice which really buggered the averages.

I think this occured after i had been away for a week and the data was being amended as a large block, similar to what is described above.

Am not currently running 24/7 due to 'wife issues' haha

Regards - Phil
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daj
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Re: Another rainfall question....

Post by daj »

did all 200 entries have the same date and time?
David
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