Author Topic: wind direction degrees?  (Read 307 times)

0 Members and 1 Guest are viewing this topic.

Online sheldon

  • Senior Member
  • **
  • Posts: 54
    • Roma EUR Meteo
wind direction degrees?
« on: December 07, 2017, 10:01:53 AM »
Hi guys,
I noticed that when I export data from weatherlink software (browse->export data), wind direction only appears as N, NE, etc., while I need to see wind direction degrees. Is this possible?
Thank you,
Andrea
My weather Station in Rome:
http://www.romaeurmeteo.it/

Offline johnd

  • Forecaster
  • *****
  • Posts: 2377
    • www.weatherstations.co.uk
Re: wind direction degrees?
« Reply #1 on: December 07, 2017, 10:18:49 AM »
I noticed that when I export data from weatherlink software (browse->export data), wind direction only appears as N, NE, etc., while I need to see wind direction degrees. Is this possible?

Not when exporting from Weatherlink, though if you're then importing into eg Excel it's presumably not difficult to convert the directions to degrees with a suitable Switch script, which will give you direction to the nearest 22.5.
Prodata Weather Systems
Prodata's dedicated Davis EnviroMonitor website
UK Davis Premier Dealer - All Davis stations, accessories and spares
Littleport, Ely, Cambs UK

Online sheldon

  • Senior Member
  • **
  • Posts: 54
    • Roma EUR Meteo
Re: wind direction degrees?
« Reply #2 on: December 07, 2017, 10:21:58 AM »
I noticed that when I export data from weatherlink software (browse->export data), wind direction only appears as N, NE, etc., while I need to see wind direction degrees. Is this possible?

Not when exporting from Weatherlink, though if you're then importing into eg Excel it's presumably not difficult to convert the directions to degrees with a suitable Switch script, which will give you direction to the nearest 22.5.

unfortunately, I need more precise values, with maximum error of about +- 5 :roll:
My weather Station in Rome:
http://www.romaeurmeteo.it/

Offline johnd

  • Forecaster
  • *****
  • Posts: 2377
    • www.weatherstations.co.uk
Re: wind direction degrees?
« Reply #3 on: December 07, 2017, 10:30:52 AM »
unfortunately, I need more precise values, with maximum error of about +- 5 :roll:

I wonder if your anemometer is mounted to an accuracy of 5 - that's really quite tricky. And pointing to True or Magnetic North? So the way that WL stores the direction data is accurate enough for most practical purposes.

But if you do need greater accuracy then you'll need to use something other than Weatherlink archive data to source the direction values. The values are available from the Weatherlink logger in the real-time LOOP packets but you'll need some software other than WLfW to capture and log them (assuming that's what you need to do).
Prodata Weather Systems
Prodata's dedicated Davis EnviroMonitor website
UK Davis Premier Dealer - All Davis stations, accessories and spares
Littleport, Ely, Cambs UK

Offline dalecoy

  • Forecaster
  • *****
  • Posts: 6026
    • Lee's Summit, MO
Re: wind direction degrees?
« Reply #4 on: December 07, 2017, 11:58:57 AM »
unfortunately, I need more precise values, with maximum error of about +- 5 :roll:

Aren't you already posting that measurement on your website at http://www.romaeurmeteo.it/   ?

http://www.romaeurmeteo.it/wugraphs.php#ui-tabs-8    (Direzione del Vento)

Online sheldon

  • Senior Member
  • **
  • Posts: 54
    • Roma EUR Meteo
Re: wind direction degrees?
« Reply #5 on: December 07, 2017, 12:20:46 PM »
Thank you all for replying! Yes, taking wind direction from Wunderground is a good idea, and I can actually solve the problem this way. I was just wonderiing why on weatherlink reports wind direction in degrees doesn't appear #-o
My weather Station in Rome:
http://www.romaeurmeteo.it/

Offline dalecoy

  • Forecaster
  • *****
  • Posts: 6026
    • Lee's Summit, MO
Re: wind direction degrees?
« Reply #6 on: December 07, 2017, 12:47:53 PM »
Thank you all for replying! Yes, taking wind direction from Wunderground is a good idea, and I can actually solve the problem this way. I was just wonderiing why on weatherlink reports wind direction in degrees doesn't appear #-o

Why do you need maximum error of about +- 5?

The specified accuracy of the Vue is only 3

And it's really hard to "aim" a Vue to precisely North - without using surveying instruments, etc.  How did you aim it (or calibrate the direction)?

I'm just curious how you're using the wind direction, that requires a maximum error of about +- 5




Online sheldon

  • Senior Member
  • **
  • Posts: 54
    • Roma EUR Meteo
Re: wind direction degrees?
« Reply #7 on: December 08, 2017, 07:07:27 AM »
Thank you all for replying! Yes, taking wind direction from Wunderground is a good idea, and I can actually solve the problem this way. I was just wonderiing why on weatherlink reports wind direction in degrees doesn't appear #-o

Why do you need maximum error of about +- 5?

The specified accuracy of the Vue is only 3

And it's really hard to "aim" a Vue to precisely North - without using surveying instruments, etc.  How did you aim it (or calibrate the direction)?

I'm just curious how you're using the wind direction, that requires a maximum error of about +- 5

I'm studying sea breeze effect, and in particular the Coriolis' force effect, which should progressively deviate wind direction of about 10-15 (from WSW to W). 
My weather Station in Rome:
http://www.romaeurmeteo.it/

Offline dalecoy

  • Forecaster
  • *****
  • Posts: 6026
    • Lee's Summit, MO
Re: wind direction degrees?
« Reply #8 on: December 08, 2017, 09:33:55 AM »
I'm studying sea breeze effect, and in particular the Coriolis' force effect, which should progressively deviate wind direction of about 10-15 (from WSW to W).

Ah!  So, the absolute accuracy of direction is less important than the precision and resolution.  And the measurements at very low wind speeds are less valuable.

Thanks for the explanation.

Offline waiukuweather

  • Forecaster
  • *****
  • Posts: 428
Re: wind direction degrees?
« Reply #9 on: December 08, 2017, 01:22:47 PM »
it is cool how a sea breeze goes around the dial like that