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[aprssig] APRS Symbol Names

Scott Miller scott at opentrac.org
Fri Jan 12 01:11:24 UTC 2007


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

> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org 
> [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of VE7GDH
> Sent: Thursday, January 11, 2007 11:58 AM
> To: aprssig at lists.tapr.org
> Subject: Re: [aprssig] APRS Symbol Names
> 
> Bob WB4APR wrote...
> 
> > So the "humanoid" figure is not just a jogger, but it let me use
> > "j" in the menu and refer to about what it looked like.  But the
> > interpretation would be that anyone who was on foot or ski's
> > or hiking boots, or snow shoes or was using an HT or other radio
> > not otherwise in a vehicle or structure, would likely use that
> > symbol.
> 
> That's a very diplomatic answer - hi! So, does that mean that 
> there will
> eventually be three symbols for scouts, and at least two symbols for
> balloons per the recent discussions on this list, but there 
> isn't room for a
> skier icon??? By your argument, the regular "truck" symbol would have
> been just fine for farm vehicles such as tractors, but there 
> were already
> separate symbols for RVs, 18 wheelers, vans, SUVs and "little 
> red cars"
> as well, and don't forget snowmobiles that have their very own symbol.
> You can't have it both ways. Either there is no room for more symbols,
> or there is enough flexibility to allow for changes such as 
> additions or
> even changes to drop little-used symbols and change the corresponding
> characters over to something that will be used more often?
> 
> What about a third symbol set? Are primary / and secondary \ 
> cast in stone,
> or can more symbol sets be added? Why not add two more symbol sets?
> That would get us up to 376 symbols. If others were added, 
> how would that
> affect legacy devices like the D7, D700 etc.? Would they be 
> capable of just
> displaying "unknown symbol" or whatever, or would they become 
> obsolete?
> 
> Also, and more importantly, who gets to decide on issues like 
> this? As near
> as I can tell, there isn't an "APRS Working Group" anymore. 
> Is APRS going to
> be absolutely static within the current confines, or will it 
> be allowed to
> progress and grow as newer and less confining hardware and software is
> developed? I think it's great that APRS can do what it 
> already does, but if
> there can't be any improvements, it might just reach a 
> critical mass and
> then collapse. If that happens, I hope I'm not around to see 
> it. I'm really
> excited about APRS and think that it should be integrated 
> into more facets
> of amateur radio instead of being seen as a separate entity.
> 
> 73 es cul - Keith VE7GDH
> --
> "I may be lost, but I know exactly where I am!"
> 
> 
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