<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
</head>
<body bgcolor="#ffffff" text="#000000">
I discovered this morning to my chagrin that I wasn't parsing the
course and speed information out of compressed packets in my
APRSISCE/32 client. I've rectified that situation, but am now faced
with a question of the interaction between compressed packet's
course/speed information versus a weather station. Page 27 (PDF's 37)
shows the CSE/SPD and DIR/SPD as the same format Data Extension where
the latter is for Weather Reports. Further, given the Complete Weather
Report Format - with Compressed Lat/Long position on page 66 (PDF 76),
it would definitely seem to be that the compressed course and speed are
in fact wind direction and speed when transmitted by a weather station
(_ symbol).<br>
<br>
Is my reading of the spec correct?<br>
<br>
Here's a sample compressed weather station packet captured from aprs.fi
in it's Decoded form:<br>
<br>
<span class="raw_line">2010-11-10 14:35:49 UTC: <b><a
href="http://aprs.fi/?c=raw&limit=&call=N9QGS">N9QGS</a></b>>APU25N,TCPIP*,qAC,CORE-2:@101435z/;0Q`9,?J_Z!bg001t045r000p000P000h84b10230/georgetownscottcountyweather.org {UIV32N}</span><br>
type: location<br>
srccallsign: N9QGS<br>
dstcallsign: APU25N<br>
latitude: 38.22749825425411 °<br>
longitude: -84.55066863380289 °<br>
course: 228 °<br>
speed: 0 km/h<br>
symboltable: /<br>
symbolcode: _<br>
messaging: 1<br>
posresolution: 0.291 m<br>
comment: /georgetownscottcountyweather.org {UIV32N}<br>
wx:<br>
pressure: 1023.0<br>
temp: 7.2<br>
wind_gust: 0.4<br>
rain_24h: 0.0<br>
humidity: 84<br>
rain_midnight: 0.0<br>
rain_1h: 0.0<br>
<br>
Note the course and speed elements outside of the wx: section. By way
of comparison, here's aprs.fi's interpretation of a non-compressed
weather packet. Note the wind_direction/speed in the wx: section.<br>
<br>
<span class="raw_line">2010-11-10 14:31:40 UTC: <b><a
href="http://aprs.fi/?c=raw&limit=&call=CW8596">CW8596</a></b>>APRS,TCPXX*,qAX,<a class="moz-txt-link-abbreviated" href="mailto:CWOP-1:@101431z2810.50N/08042.27W_324/001g004t066r000p000P000h79b10189.DsVP">CWOP-1:@101431z2810.50N/08042.27W_324/001g004t066r000p000P000h79b10189.DsVP</a></span><br>
type: location<br>
srccallsign: CW8596<br>
dstcallsign: APRS<br>
latitude: 28.175 °<br>
longitude: -80.7045 °<br>
symboltable: /<br>
symbolcode: _<br>
messaging: 1<br>
posresolution: 18.52 m<br>
posambiguity: 0<br>
comment: .DsVP<br>
wx:<br>
wind_direction: 324<br>
pressure: 1018.9<br>
rain_1h: 0.0<br>
wind_gust: 1.8<br>
temp: 18.9<br>
rain_24h: 0.0<br>
wind_speed: 0.4<br>
rain_midnight: 0.0<br>
humidity: 79<br>
<br>
Depending on the answer(s) to my assumption, I'll either be changing my
interpretation that compressed course and speed for weather stations
actually is the wind direction and speed, or I'll be contacting Hessu
to fix up aprs.fi so that it begins treating compressed course and
speed as wind direction and speed for weather which he currently
doesn't seem to be doing.<br>
<br>
Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32<br>
<br>
</body>
</html>