04 Jan 2010  Previous update

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


19 Sep 11:  Added T and 2 overlays for TX 1 and 2 hop IGates
            Added overlays to (;) portable, to show event types
23 Mar 11:  Added Radiation Detector (RH)
20 Apr 10:  Byonics requested (BY)
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:


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


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 

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.

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

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

/& = HF Gateway  <= the original primary table definition
I& = Igate Generic (please use more specific overlay)
R& = Receive only IGate (do not send msgs back to RF)
T& = TX igate with path set to 1 hop only)
2& = TX igate with path set to 2 hops (not generally good idea)

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

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

/- = 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

E0 = Echolink Node (E0)
I0 = IRLP repeater (I0)
S0 = Staging Area  (S0)
W0 = WIRES (Yaesu VOIP)

88 = 802.11 network node (88)
G8 = 802.11G  (G8)

/; = Portable operation (tent)
\; = Park or Picnic
F; = Field Day
I; = Islands on the air
S; = Summits on the air

ADVISORIES: #<  (new expansion possibilities)
/< = motorcycle
\< = Advisory (single gale flag)

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

BOX SYMBOL: #A (and other system inputted symbols)
/A = Aid station
\A = numbered box
9A = Mobile DTMF user
7A = HT DTMF user
HA = House DTMF user
EA = Echolink DTMF report
IA = IRLP DTMF report
RA = RFID report
AA = AllStar DTMF report
DA = D-Star report
XA = OLPC Laptop XO

/E = Eyeball for special live events
\E = (existing smoke) the symbol with no overlay
HE = (H overlay) Haze
SE = (S overlay) Smoke
BE = (B overlay) Blowing Snow         was \B
DE = (D overlay) blowing Dust or sand was \b
FE = (F overlay) Fog                  was \{

/H = hotel
\H = Haze
RH = Radiation detector (new mar 2011)
WH = Hazardous Waste
XH = Skull&Crossbones

\R = Restaurant (generic)
7R = 7/11
MR = McDonalds
TR = Taco Bell

/Y = Yacht  <= the original primary symbol
\Y =        <= the original alternate was undefined
AY = Alinco
BY = Byonics
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

/a = Ambulance
Da = DARES Dutch AR Emergency Services
Ga = RSGB Radio Society of Great Brittan
Sa = SATERN Salvation Army
Wa = WinLink

/c = Incident Command Post
\c = Civil Defense
Sc = SATERN mobile canteen

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

/k = truck
\k = SUV
4k = 4x4
Ak = ATV (all terrain vehicle)

/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:


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. 

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