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ZL3AI > APRDIG 15.01.07 00:50l 144 Lines 5140 Bytes #999 (0) @ WW
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From: ZL3AI@ZL2BAU.#79.NZL.OC
To : APRDIG@WW
Message: 7
Date: Thu, 11 Jan 2007 17:11:24 -0800
From: "Scott Miller" <scott_at_opentrac.org>
Subject: RE: [aprssig] APRS Symbol Names
If we ever do a total rework of the APRS symbol set, I'm going to advocate a
hierarchical system like the one I proposed for OpenTRAC, which borrowed
heavily from MIL-STD-2525B.
Instead of just a symbol for car or truck, it goes like this:
3 - Ground
3.2 - Equipment
3.2.1 - Vehicles
3.2.1.1 - Passenger
3.2.1.1.1 - Car
3.2.1.1.2 - Van
3.2.1.1.3 - Truck
3.2.1.1.4 - SUV
3.2.1.1.5 - RV
3.2.1.1.5.1 - Class A
3.2.1.1.5.2 - Class B
And so on. Ballons would go under:
2 - Air
2.1 - Lighter than air
2.1.2 - Unmanned
2.2.2.2 - Experimental
The primary advantage is that you don't need to know all of the symbols in
advance. If a new type of passenger vehicle is added to the list, old
clients still know that it's a passenger vehicle and can display an
appropriate icon. It's also simple to filter on all ground vehicles, all
aerial units, all special events, and so on.
As for actual on-air encoding, OpenTRAC packs two digits (1-16) per byte,
so 3.2.1.1.5.1 actually encodes as a 3-byte sequence. APRS could probably
get by just fine with four characters for symbols and still stay with
printable characters.
Of course, you could get more than 8000 symbols from just two printable
characters, but that doesn't give you a nice hierarchical structure.
MIL-STD-2525B (Common Warfighting Symbology) makes for interesting reading.
APRS could learn a lot from it, though I think it'd be possible to make
some of the symbols a little clearer. The important thing is that it
assigns specific meanings to colors, borders, and other modifiers that are
applied in a consistent way. APRSdos seems to come the closest to this of
any APRS client I've ever seen. Applying this stuff appropriately could
really help people who use APRS for serious tactical uses, but it might be
overload for casual users who just want to see cars on a map.
Scott
N1VG
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Message: 8
Date: Thu, 11 Jan 2007 17:31:06 -0800
From: "Keith - VE7GDH" <ve7gdh_at_rac.ca>
Subject: RE: [aprssig] APRS Symbol Names
Scott N1VG wrote...
>If we ever do a total rework of the APRS symbol set, I'm going
>to advocate a hierarchical system like the one I proposed for
>OpenTRAC, which borrowed heavily from MIL-STD-2525B.
That sounds like a sensible way to go. With 8000 symbols available, there
wouldn't be any argument for not adding a symbol that was needed, and I
wouldn't squawk about 3 symbols for scouts, 2 for balloons or 7 or more for
vehicles and the existence of a few that were little used or never used
when there is supposedly no room to add a skier symbol. I'm very
enthusiastic about APRS. I want it to move forward when needed. A change
like that would allow us to expand the capabilities of it as needed. Much
of APRS has been "seat of the pants, design it as we go along". We had to
start somewhere, but maybe it is time to look at where we want to go from
here. I'm not advocating chucking the whole spec out, but now that we have
used it for a while, perhaps a clearer picture of what we want to add or
change will become more apparent.
73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am!"
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Message: 9
Date: Thu, 11 Jan 2007 23:50:44 -0500
From: Steve Huston <huston_at_srhuston.net>
Subject: Re: [aprssig] APRS Symbol Names
On 1/11/07 8:31 PM, Keith - VE7GDH wrote:
>I'm not advocating chucking the whole spec out, but now that we have
>used it for a while, perhaps a clearer picture of what we want to add
>or change will become more apparent.
I'm sorry, I have to say it...
But won't someone think of the children! er, I mean, Kenwoods!
In fairness though, a hierarchical system like that makes perfect sense
- similar to how SNMP and LDAP OIDs are setup. The end result is that
you don't have to know exactly what all the numbers mean, if you've got
an idea of what they mean up to a certain point; from there you can
either guess or just present it as-is.
--
Steve Huston - W2SRH - Unix Sysadmin, Dept. of Astrophysical Sciences
Princeton University | ICBM Address: 40.346525 -74.651285
126 Peyton Hall |"On my ship, the Rocinante, wheeling through
Princeton, NJ 08544 | the galaxies; headed for the heart of Cygnus,
(609) 258-7375 | headlong into mystery." -Rush, 'Cygnus X-1'
------------------------------
Message: 10
Date: Fri, 12 Jan 2007 05:18:29 -0800 (PST)
From: Matt Murphy <web8ck_at_yahoo.com>
Subject: [aprssig] Re: buoys...
Hey Jim,
A good Reference that I have used is the ISS Fan Club at:
http://www.issfanclub.com. They have digi and other mode info down the
right side. http://www.ariss.net will show the time the digi was last
heard. The same for PCSat, Ande, and Raft here:
http://www.findu.com/cgi-bin/pcsat.cgi?absolute=1.
73,
Matthew, kc8bew
------------------------------
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