If I can remember the incantations to compile Xastir on a new CentOS 5
install I'll look at these tomorrow. I'm reinstalling my machine at
home tomorrow, I hope. Otherwise I'll look on the laptop... Then I'll
see if we're representing things correctly. I know that Dale's going
outta the business of the WxSrv stuff but we're trying to see how to
carry on and provide real and timely information.
gc
Tom Russo wrote:
On Thu, Sep 04, 2008 at 02:10:28PM -0500, we recorded a bogon-computron collision of
the <[EMAIL PROTECTED]> flavor, containing:
I'm looking at Hanna and Ike on Xastir, but each has a number of
circles, red, green, yellow around them. Would someone in the know
please give me (and the rest of us land lubbers) the skinny on this,
tell us how all this happens.
Are you asking what the different circles mean? I was able to figure this
out by looking at the APRS spec and the source code in db.c --- I was unable
to find any documentation of these circles anywhere else.
They're the radius of various wind speed ranges as predicted by the NWS.
The red circle is the reported (or predicted) radius of hurricane force winds,
the green the radius of gale-force winds, and the yellow the radius of tropical
storm winds. The packet that contains that information also has information
about the true ranges and speeds in the report.
Some of the reports are predictions X hours in the future. So HANNA+24h is
the prediction for where HANNA will be in 24 hours and how strong it's
predicted to be.
It's not clear to me that Xastir displays all the information available in
the packet. I looked over some of the recent data using the perl APRS decoder
(ftp://ftp.eskimo.com/u/a/archer/aprs/Ian_Wade/aprsdecu.tar.gz)
and there seems to be a lot more there than Xastir is showing in the Station
Info dialog for the object. For example, I just grabbed this packet out of
my logs:
NHCTCM>APRS,qAS,WXSVR:;[EMAIL
PROTECTED]/010/TS/055^065/0989>000&275%090zkIqzhhzzzzz{4FDA0
which the perl aprs decoder shows as:
APRS Data Type= Object
Object Name= 'HANNA_ato' Object Status= Live
Day= 04 Time= 21 hours 00 mins UTC
Lat= 24 deg 30.00 min N Long= 73 deg 30.00 min W
Icon= Hurricane Overlay= **BAD OVERLAY CHAR 'S' not allowed with this symbol
Wind Direction= 315 deg Speed= 010 knots (11.5 mph 18.5 kph 5.1 m/s)
Tropical Storm: Sustained Wind Speed= 055 knots (63.3 mph 101.9 kph 28.3 m/
s)
Peak Wind Speed= 065 knots (74.8 mph 120.4 kph 33.4 m/s)
Central Pressure= 989 mbar/hP
Radius of Hurricane Winds= 0 nautical miles (0 miles 0 km)
Radius of Tropical Storm Winds= 275 nautical miles (316 miles 509 km)
Radius of Whole Gale Winds= 90 nautical miles (104 miles 167 km)
There could also be multi-point data hidden in the comment, but I'm not sure.
There's additional information here that I'm not sure is captured anywhere
in documentation I can find: for example, what's the overlay character
signify?
Gerry: do you know whether the data after the gale winds data is meant to
be a multipoint descriptor, and whether the overlay character is supposed to
mean anything in particular? The wxsvr.net web site appears to be gone for
good and the documentation that was once there is no longer available.
--
Gerry Creager -- [EMAIL PROTECTED]
Texas Mesonet -- AATLT, Texas A&M University
Cell: 979.229.5301 Office: 979.862.3982 FAX: 979.862.3983
Office: 1700 Research Parkway Ste 160, TAMU, College Station, TX 77843
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