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Avereage Windspeed?
Posted: Thu Jan 29, 2009 3:13 pm
by AAMFlyer
Quick Dumb Question... The WDL dial for windspeed is an Average Windspeed - does anyone know what that average time is...? Is it 10 minutes? Thanks!
Re:Avereage Windspeed?
Posted: Wed Mar 25, 2009 6:37 am
by AAMFlyer
Boris,
Do you by change know what this is - I believe it is the 2nd data element in the clientraw file and is listed as avg windspeed.... Avereage of what time though - 10 minutes....or is it more? Thanks!
Re:Avereage Windspeed?
Posted: Wed Mar 25, 2009 11:25 am
by skyewright
AAMFlyer wrote:Do you by change know what this is - I believe it is the 2nd data element in the clientraw file and is listed as avg windspeed....
IIRC the mechanism for the clientraw files basically involves some very fancy HTML templates.
If I'm correct then if you found those files you'd find the answer?
I think the location of the templates was mentioned on the Forum at some time, but I've not been able to find the relevant message. I you find them I'd be interested to know where they are too.
Failing that have you tried comparing the value against graphs using various "bucket" sizes?
Or maybe studying wind0-min10, etc. in the weather folder?
Re:Avereage Windspeed?
Posted: Wed Mar 25, 2009 8:11 pm
by skyewright
AAMFlyer wrote:I believe it is the 2nd data element in the clientraw file and is listed as avg windspeed.... Avereage of what time though - 10 minutes....or is it more?
I found the templates (by realising that Linux must have a tool for finding files, and discovering the locate tool...).
The file is:
\\home\\meteohub\\clientraw.conf
and the first 3 fields (after the initial 12345 marker) are:
[actual_wind0_speed_kn:-] [actual_wind0_gustspeed_kn:-] [actual_wind0_dir_deg:-]
Re:Avereage Windspeed?
Posted: Thu Mar 26, 2009 6:05 am
by AAMFlyer
You kind of lost me - somewhere it has to be actually calculating an average and there is no field or meteohub marker for average that I can find.... Comparing to my Davis console - it looks to be a 10 minute avereage as those measure close to each other on the 10 min avg..
When you parse the clientraw file - you get this..
Field# Label Type Contents
000 Header L 12345
001 Avg Speed K 5.2 kts = 5.98 mph = 9.63 km/h
http://www.tnetweather.com/wd-parser.php
I guess I will call it a 10 min avg at this time...
Re:Avereage Windspeed?
Posted: Thu Mar 26, 2009 12:55 pm
by skyewright
AAMFlyer wrote:You kind of lost me - somewhere it has to be actually calculating an average and there is no field or meteohub marker for average that I can find....
A lot the figures are implicitly averages e.g. [last60m_wind0_speed_mph] is the (average) windspeed over the last 60 minutes.
Comparing to my Davis console - it looks to be a 10 minute avereage as those measure close to each other on the 10 min avg..
From my earlier analysis, the meteohub value being used is [actual_wind0_speed_kn], which I believe is the most recently received windspeed reading in knots.
Edit: Because the Davis VP2 issues wind data at such a high rate, I have a feeling that 'actual' may have a slightly different meaning in that case in order to prevent excessively large Meteohub raw data files? Perhaps a 1 minute average?
Re:Avereage Windspeed?
Posted: Thu Mar 26, 2009 4:40 pm
by AAMFlyer
That's a good point on the Davis.... I always thought it was simply taking the most recent reading (which for the Davis is every 2.5 seconds) - but then WDL labels it as Average Windspeed....so it would be nice to know what the avg really is....
Perhaps Boris can chime in hear to see what that "actual_wind0_speed_kn" really is when adding it to the clientraw file...is the a snap shot or the most current reading or an average over 1 min, 10 min etc.... But so far it seems to match the 10 min avg on the Davis Console....
Thanks!