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Old April 23rd 05, 04:02 AM
Brenor Brophy
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For those that are interested a very well written piece of Open Source
software for decoding METARs is called PHPWeather and is available at
http://phpweather.sourceforge.net/. PHP is a script language that runs on a
web server and outputs HTML to your browser. As computer languages go, it is
not very intimidating to anyone with basic programming skills.

For an example of its output here is the translations for the following
METAR from Reid Hillview Airport:

KRHV 230149Z 20008KT 10SM SCT045 SCT065 BKN150 15/07 A2990

"This is a report for San Jose / Reid / Hillv, United States. The report was
made one hour and 3 minutes ago, at 01:49 UTC. The wind was blowing at a
speed of 4.1 meters per second (9.2 miles per hour) from south/southwest
(200°). The temperature was 15 °C (59 °F), with a dew-point at 7 °C (45 °F).
The atmospheric pressure was 1013 hPa (29.90 inHg). The relative humidity
was 58.7%. There were scattered clouds at a height of 1372 meter (4500
feet), scattered clouds at a height of 1981 meter (6500 feet), and broken
clouds at a height of 4572 meter (15000 feet). The overall visibility was
16.1 kilometers (10.0 miles). "

I have had a lot of fun with this software. An early version of an
application that uses it, that I am working on can be seen on my
webpage(http://www.brenorbrophy.com/). It is called Micro Wx - it outputs a
small (both screen image and bytes) current weather summary suitable for a
web capable cell phone. Before anyone chimes in with how this has been done
before - I know, but it hasn't been done exactly the way I want it and my
version has. Funnily enough, I would have originally agreed strongly with
the OP - why the hell do we still work with these abbreviations invented for
the bandwidth of a telex machine in the era of the Internet. Well now it
appears your typical wireless cellphone connection (and tiny screen) has
taken us back to telex style.

-Brenor

"Nathan Young" wrote in message
...
On Fri, 22 Apr 2005 14:35:52 -0400, Peter Clark
wrote:

On Fri, 22 Apr 2005 12:37:54 -0500, wrote:

KHSV 221553Z 19009KT 6SM BR FEW020 BKN035 OVC100 19/18 A2986 RMK
AO2 TSE00RAE11 SLP104 TS MOV NE P0000 T01890178=

I know, and I can read it. And someone is going to say that they
prefer it that way.

I can just see an ASR-33 Teletype machine jumping up and down and
saying that 10 characters per second is what God made for us.


How about FDL uplinks? I think they're only around 30K/s. I'd rather
see that used uploading the Nexrad info rather than English form
METAR.

The translation of the raw data is trivial to do in the client end of
the system (a-la the Bendix KDR510/810, or the XM weather in the
G1000, it shows both decoded and raw-data TAF and raw-data METAR if
available for the reporting stations).


It is not as trivial as it should be. METAR decoder software is
difficult to write because of the special weather statements that can
be included in a METAR entry (things like RVR, multiple precip types,
etc).

Simple parsers can grab winds, date, time, and cloud conditions. But
to be all-encompassing requires a bit more. I found a package (via
NOAA?) that would do METAR decodes, and it included approximately 30KB
of source code, which seemed like a lot for the extra bit of
functionality it provided.