[Xastir] Re: Wind Gusts

[Curt, WE7U]

On Thu, 14 Dec 2006, Clay Jackson wrote:

> if you look at my data going to findu, it's now reporting much more
> reasonable gust (32MPH so far this evening, the power's out and the
> storm "center" is still several hours away).

Ok.  Wind speed as transmitted on APRS is supposed to be:
"sustained one-minute wind speed (in mph)".  Gust is supposed to be:
"peak wind speed in the last 5 minutes".  Page 64 of the APRS spec.
I saw nothing in the addendums to change these.

Now... Some weather stations don't give us any gust or peak value,
others give it or the wind speed to us with a different time period.

What would be the correct thing to do?

My thoughts are that if we can get a peak value from the weather
station, we maintain our own record of the "gust" value by keeping
track of the highest peak for the preceeding five minutes, as best
we can (keeping them in qty. 5 "minute" buckets instead of qty. 300
"second" buckets).

For the wind speed, we need to have it be a 1-minute sustained
speed, however we get that.

Some weather stations feed us direct values for these and some
don't, plus some stations may calculate things differently, or
average over different intervals than we wish.  Is it better to add
extra code to use their values over our computed values, or better
to compute them ourselves?  I chose to compute them, for
consistency.

It also sounds like the values requested by NOAA are different than
the APRS spec dictates we transmit.

--
Curt, WE7U.   APRS Client Comparisons: http://www.eskimo.com/~archer
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