Received: from opus.hpl.hp.com by jr.hpl.hp.com with ESMTP (1.37.109.24/15.5+ECS 3.3+HPL1.1) id AA006817720; Tue, 20 Jul 1999 17:42:20 -0700 Return-Path: <david@windcall.com-DeleteThis> Received: from hplms26.hpl.hp.com by opus.hpl.hp.com with ESMTP (1.37.109.24/15.5+ECS 3.3+HPL1.1) id AA105307708; Tue, 20 Jul 1999 17:41:48 -0700 Received: from reporter.windcall.com (reporter.windcall.com [208.2.178.130]) by hplms26.hpl.hp.com (8.9.1a/HPL-PA Relay) with ESMTP id RAA02976 for <wind_talk@opus.hpl.hp.com-DeleteThis>; Tue, 20 Jul 1999 17:41:47 -0700 (PDT) Received: from pokey (pokey.windcall.com [206.55.225.82]) by reporter.windcall.com (8.8.7/8.8.7) with SMTP id RAA26059; Tue, 20 Jul 1999 17:32:04 -0700 From: "David St. John" <david@windcall.com-DeleteThis> To: "Sergei Burkov" <bilbo@bilbo.com-DeleteThis> Cc: "Multiple recipients of list" <wind_talk@opus.hpl.hp.com-DeleteThis>, "Jim Martin" <jim@windcall.com-DeleteThis> Subject: RE: Why are the reports useless? Date: Tue, 20 Jul 1999 17:36:04 -0700 Message-Id: <000401bed311$03e7cbe0$52e137ce@pokey.windcall.com-DeleteThis> Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-Msmail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 Importance: Normal In-Reply-To: <Pine.LNX.3.96.990714074814.9128A-100000@shell.accesscom.com-DeleteThis> X-Mimeole: Produced By Microsoft MimeOLE V4.72.3110.3
Hi Sergei,
Thanks for the comments. Sorry for the late response, but my wife and I
(mostly my wife ;) were busy having a baby boy! A brand new little
windsurfer-to-be. How soon can he start? Anyone know what the youngest
kid's rig made is?
I've followed most of this thread, I think. And I think I can answer some
of your questions.
> As callwind is concerned, it's more clear. The guys calibrate their
> readers. I.e., what they show us is not what they get from sensors.
> They make corrections trying to project what is on the water from
> what they measure on shore.
Yes, it's true that we *sometimes* calibrate the readings our sensors give
us in an effort to give our members the most accurate data possible. Since
we don't have sensors out on the water (yet!), we adjust the reading for
certain directions when the anemometer does not have a clear view of the
wind out on the water. Crissy field is the classic example - it can be
glassy on the beach and a steady 25 knots at Anita Rock. So, we make
adjustments to certain directions (about 20% to the SW reading) to give
members the closest estimate of what the wind is doing. But sometimes the
best the sensors can give you is just that: an estimate.
However, for the vast majority of our sensors, you are seeing the actual
reading - for most sites the wind on the shore is a pretty good gauge of the
wind on the water. We make adjustments only after receiving lots and lots
of feedback from from sailors at the particular site who have volunteered
their input to help us make the system better. The adjustments usually
happen in the first couple months of service - we rarely change them once
the initial calibration is set. Since we know that people who sail
particular sites regularly make their own mental calibrations (as you
mentioned), we send out a message on the pager if ever a site's calibration
is changed (again, that's very rare after the first few months a sensor is
in service).
The "field research" we've done confirms that the vast majority of our
members would rather have the sensors calibrated than not.
> Trouble is, their correction function
> is apparently does not take into consideration the wind direction.
Actually, as I mentioned above, our correction does take direction into
consideration. We can adjust each of the 16 direction points individually
from -50% to +50% actual reading.
> I believe the callwind guys who carge for their service should consider
> investing part of the proceeds into installing sensors on buoys, bridge
> pillars, barges at 3rd, Anita rock, etc. Who needs wires in the midst of
> Silicon Valley these days?
We would love to have wireless wind sensors on the pillars, barges, buoys,
everywhere! The technology, however, is not really the issue - it's getting
the permission to put our sensors there. The vast majority of our revenue
goes into the legwork necessary to acquire rights to, and install sensors
at, new windsurfing sites; the rest goes into better technology and better
information delivery mechanisms. No one is getting rich here, or even
making a profit - we do this because we love it.
> 1. Post TWO wind reports, with:
> - raw data
> - corrected data
Posting two reports - raw and corrected - is a nice idea, but sure would be
a pain to implement, and I think more confusing to most of our members.
> 2. Announce any changes to the correction coefficients
Finally, as I mentioned above, we *do* notify members when a change is made
after the first "breaking-in" phase of a new sensor. And in the next
iteration of our website we will have much more local information, including
sensor notes and correction factors. So stay tuned!!
-- David St. John Call of the Wind http://www.windcall.com/
This archive was generated by hypermail 2b29 : Mon Dec 10 2001 - 02:35:51 PST