APRS SYMBOL OVERLAY and EXTENSION TABLES in APRS 1.2 04 Jan 2010
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BACKGROUND: This file addresses new additions proposals (OVERLAYS)
to the APRS symbol set after 1 October 2007. The master symbol
document remains on the www.aprs.org/symbols/symbolsX.txt page.


NOTE: There was confusion with different copies of this file on
different web pages and links. THIS file is now assumed to be the
CORRECT one.


UPDATES/REVISIONS/CORRECTIONS:

04 Jan 10: added #A to the table (correcting earlier omission)
12 Oct 09: Added W0 for Yaesu WIRES nodes
09 Apr 09: Changed APRStt symbol to overlayed BOX (#A)
21 Aug 08: Added RFID R=, Stroller B], Radios#Y, & skull&Xbones (XH)
27 Apr 08: Added some definitions of the numbered circle #0.
25 Mar 08: Added these new definitions of overlays:

\A - (BOX symbol) APRStt(DTMF), RFID users, XO (OLPC)
\' - Was Crash Site. Now expanded to be INCIDENT sites
\% - is an overlayed Powerplant. See definitions below
\H - \H is HAZE but other H overlays are HAZARDs. WH is "H.Waste"
\Y - Overlays for Radios and other APRS devices
\k - Overlay Special vehicles. A = ATV for example
\u - Overlay Trucks. "Tu" is a tanker. "Gu" is a gas truck, etc
\< - Advisories may now have overlays
\8 - Nodes with overlays. "G8" would be 802.11G
\[ - \[ is wall cloud, but overlays are humans. S[ is a skier.
\h - Buildings. \h is a Ham store, "Hh" is Home Depot, etc.

Previous edition was 4 Oct 2007.

In April 2007, a proposal to expand the use of overlay bytes for
the extension of the APRS symbol set was added to the draft APRS1.2
addendum web page. The following document addresses that proposal:

www.aprs.org/symbols/symbols-overlays.txt

For details on Upgrading your symbol set, please see the background
information on Symbols prepared by Stephen Smith, WA8LMF:

www.aprs.org/symbols/symbols-background.txt

CONSISTANCY: Since the objective of APRS is consistent, reliable
communications at the local level, there has been a hesitance to
making significant changes to the APRS symbol set. The Integrity
of APRS depends on everyone seeing the same information at the
same time. Frequent changes to the symbol sets can actually
undermine that integrity and operational utility of APRS and end up
with worse outcomes due to miss-communications than the lack of any
particular symbol might suggest.

OVERLAY HISTORY: When the overlay symbol set was first defined for
the original APRS back in 1995, it had the potential to expand the
APRS symbol set from the 94 original primary symbols to a secondary
set that could each have as many as 36 diffeernt overlays on each of
those secondary symbols up to almost 3500 combinations. But some
authors then could not easily implement these overlays, except by
one-by-one exceptions to their code.

For this reason, a compromise was made with those authors and then
eventually written into the APRS spec to limit overlays to only a
small subset of alternate symbols. Those original overlayable
alternate symbols were labeled with a "#" and called "numbered"
symbols. (UIview requires "No." in the symbols.ini file)

STATUS OF OVERLAYS 1 OCTOBER 2007: the APRS symbol set only had a
few remaining unused symbol codes that had not yet been defined:

OF THE 94 Primary Symbols. The following were available:
10 symbols (/0 - /9) that mostly look like billiard balls now
4 symbols /D, /J, /Q, /z were undefined or TBD
2 were reserved

OF THE 94 Alternate Symbols. The following were available:
3 undefined series \=, \Y, \Z which could do 36 overlays
8 series \1 through \8 that can support 36 overlays each
3 reserved series.

ADDITIONAL OVERLAY PROPOSAL: But any of the other 79 alternate
symbols could all have multiple (36) overlays if they can make sense
with the existing underlying basic symbol that we have been using for
that basic alternate symbol. That is, any new definition of a
previously unused overlay character will have undefined results on all
prior APRS systems and should be used with caution. But the symbol
set is extensible with these cautions. (See the Proposal that would
expand the APRS symbol set to over 3200 at the bottom of this
document.)


SYMBOL OVERLAY TABLES: This document will keep track of all
definitions of overlays on all ALTERNATE symbols. Although these
overlays were originally intended to just overlay a displayable
single character on a basic symbol, there is no prohibition against
taking the combination of a symbol and specific overlay, and then
letting that define a new graphic just for that combination.

The following tables will attempt to keep track of these and
any other useful generic applications of overlay characters.

POWER PLANT: #%
/% = DX cluster <= the original primary table definition
C% = Coal
G% = Geothermal
H% = Hydroelectric
N% = Nuclear
S% = Solar
T% = Turbine
W% = Wind

INCIDENT SITES: #'
\' = Airplane Crash Site <= the original primary deifinition
A' = Automobile crash site
H' = Hazardous incident
M' = Multi-Vehicle crash site
P' = Pileup
T' = Truck wreck

APRStt or DTMF or RFID gated users: #A (was BOX symbol)
MA = Mobile DTMF user
HA = HT DTMF user
QA = QTH DTMF user
EA = Echolink DTMF report
IA = IRLP DTMF report
RA = RFID report
EA = Event DTMF report
etc

HUMAN SYMBOL: #[
/[ = Human
\[ = Wall Cloud (the original definition)
B[ = Baby on board (stroller, pram etc)
S[ = Skier * <= Recommend Special Symbol
R[ = Runner
H[ = Hiker

CARS: #>
/> = normal car (side view)
\> = Top view and symbol POINTS in direction of travel
E> = Electric
H> = Hybrid
S> = Solar powered
V> = GM Volt

HOUSE: #-
/- = House
\- = (was HF)
5- = 50 Hz mains power
6- = 60 Hz mains power
B- = Backup Battery Power
E- = Emergency power
G- = Geothermal
H- = HF
O- = Operator Present
S- = Solar Powered
W- = Wind powered

NUMBERED CIRCLES: #0
E0 = Echolink Node (E0)
I0 = IRLP repeater (I0)
S0 = Staging Area (S0)
W0 = WIRES (Yaesu VOIP)

NETWORK NODES: #8
88 = 802.11 network node (88)
G8 = 802.11G (G8)

BOX SYMBOL: #A
/A = Aid station
\A = numbered box
XA = OLPC laptop XO
#A = all others for DTMF or RFID

HAZARDS: #H
/H = hotel
\H = Haze
WH = Hazardous Waste
XH = Skull&Crossbones

RESTAURANTS: #R
\R = Restaurant (generic)
7R = 7/11
KR = KFC
MR = McDonalds
TR = Taco Bell

RADIOS and APRS DEVICES: #Y
/Y = Yacht <= the original primary symbol
\Y = <= the original alternate was undefined
AY = Alinco
IY = Icom
KY = Kenwood * <= Recommend special symbol
YY = Yaesu/Standard* <= Recommend special symbol

GPS devices: #\
/\ = Triangle DF primary symbol
\\ = was undefined alternate symbol
A\ = Avmap G5 * <= Recommend special symbol

ATM Machine or CURRENCY: #$
/$ = original primary Phone
\$ = Bank or ATM (generic)
U$ = US dollars
L$ = Brittish Pound
Y$ = Japanese Yen

ARRL or DIAMOND: #a
/a = Ambulance
Aa = ARES
Da = DARES Dutch AR Emergency Services
Ga = RSGB Radio Society of Great Brittan
Ra = RACES
Sa = SATERN Salvation Army
Wa = WinLink

CIVIL DEFENSE or TRIANGLE: #c
/c = Incident Command Post
\c = Civil Defense
Rc = RACES
Sc = SATERN mobile canteen

BUILDINGS: #h
/h = Hospital
\h = Ham Store ** <= now used for HAMFESTS
Hh = Home Dept etc..

SPECIAL VEHICLES: #k
/k = truck
\k = SUV
4k = 4x4
Ak = ATV (all terrain vehicle)

TRUCKS: #u
/u = Truck (18 wheeler)
\u = truck with overlay
Gu = Gas
Tu = Tanker
Cu = Chlorine Tanker
Hu = Hazardous


Anyone can use any overlay on any of the overlayable symbols for any
special purpose. We are not trying to document all possible such
overlays. The purpose of this document is to help keep a list of
more common such definitions that have more universal use and for
which multiple definitions would lead to confusion.

Future APRS code writers should be aware of where we are going:

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PROPOSAL TO ASSIGN MANY MORE BLOCKS OF SYMBOL SETS April 2007
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www.aprs.org/symbols/symbols-overlays.txt

In the initiative to upgrade APRS symbols, we are wasting some
very valuable OVERLAYABLE symbol subgroups with a few nailed
down legacy weather symbols. We are proposing to consolidate
some of these Weather symbols to open up much more space. Since
this is the first time we have considered actually CHANGING some
symbol definitions, this can cause problems out there for some
users of some legacy systems.

That is why I am posting this plan to the APRS community. If we
do this, XASTIR and UIVIEW will be able to download new symbol
definitions. But some legacy clients that do not operate from
external symbol files will show the wrong symbols for these. If
users of those systems forsee some serious problems with the
re-arrangement of these symbols, let us know the specific impact
and your ideas for a workaround..

The symbols that would be impacted are as follows:

First, consolidate all of the visibility symbols into the old
SMOKE symbol and change its meaning to "VISIBILITY", and then
differentiate them with the overlay characters.

"\E" (existing smoke) the symbol with no overlay
"HE" (an H overlay) will mean Haze
"SE" (an S overlay) will mean Smoke
"BE" (a B overlay) will mean Blowing Snow was \B
"DE" (a D overlay) will mean blowing Dust or sand was \b
"FE" (an F overlay) will mean Fog was \{

Another category is to expand the RAIN symbol to make it kinda
like lots of angled dots coming from the sky, but with an open
center so that we can use overlays for a number of common
PRECIPITATIONS. The consolidations would be:

"\`" (existing Rain) would be the symbol with no overlay
"R`" (an R overlay) would mean Rain
"F`" (an F overlay) would mean Freezing Rain was \F
"H`" (an H overlay) would mean Hail was\:
"D`" (an D overlay) would mean Drizzle was \D
"E`" (an E overlay) would mean slEEt was \e
"S`" (an S overlay) would mean Snow was \*
Etc. and other particulates coming from the sky

Next, I propose expanding the existing RAIN SHOWER "\I" symbol
to look like some kind of cloud symbol with specks in it that
can be overlayed. (It needs to look different from the next
CLOUD symbol). It can then consolidate these symbols:

"RI" (an R overlay) would mean Rain Shower
"SI" (an S overlay) would mean Snow shower was \G
"LI" (an L overlay) would mean Lightening was \J
Etc. and other things related to clouds

Next, I propose expanding the existing CLOUD symbol to allow
definition of any number of different types of cloud. This
needs to also look like a cloud but a different shape and allow
for overlays (Maybe this cloud is clear):

"\(" is the existing cloud symbol (would have no overlay)
"P(" with P overlay would mean partly cloudy was \p
"W(" with W overlay would be a wall cloud was \[
"F(" would be Funnel cloud, but the original "\f" will also be
retained for now

All of these initiative will free up a lot of overlayable symbol
GROUPS each of which can suport up to 36 different overlays in
each group for the future:

#H for 36 new Hazards (was only Hail)
#[ for 36 new human symbols (was only Wall Cloud)
#\ for 36 new GPS or navigation equipment
#B TBD. \B was only blowing snow now is BE
#b TBD. \b was only blowing dust/sand now is DE
#{ TBD. \{ was only fog now is FE
#* TBD. \* was snow only now is S`
#: TBD. \: was hail only now is H`
#D TBD. \D was drizzle only now is D`
#F TBD. \F was freezing rain only now is F`
#e TBD. \e was sleet only now is E`
#G TBD. \G was only Snow shower now is SI
#J TBD. \J was only Lightening now is LI
#p TBD. \p was only partly cloudy now is P(

Of course future code can fully draw each of these overlays as
distinct special symbols in any way they want. But Uiview uers
are stuck with only seeing overlays on basic group shapes for
now.

To keep the noise-to-signal rate down, I suggest replying only
if you have something of significance that will be impacted by
this proposal. I especially want to hear from Dale Hugley who
is a resource for weather, and Stephen Smith who will have to
draw them for Uiview. And others with a stake in this...

Bob Bruninga, WB4APR