APRS SYMBOL OVERLAY and EXTENSION TABLES in APRS 1.2 13 May 2008 --------------------------------------------------------------------- Updated April 2008: Added some definitions of the numbered circle #0. Updated 25 Mar 2008: Added these new definitions of overlays: \= - APRStt Touchtone users (DTMF) \' - 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. BACKGROUND: This file addresses new additions (OVERLAYS) to the APRS symbol set after 1 October 2007. The master symbol document remains on this page and documents all other non-overlay symbols and updates: http://www.ew.usna.edu/~bruninga/aprs/symbolsX.txt 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: http://www.ew.usna.edu/~bruninga/aprs/symbols-overlays.txt For details on Upgrading your symbol set, please see the background information on Symbols prepared by Stephen Smith, WA8LMF: http://www.ew.usna.edu/~bruninga/aprs/symbols-background.txt OBJECTIVES: 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. 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. STATUS AS OF 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 are available: 10 symbols (/0 - /9) that mostly look like billiard balls now 4 symbols /D, /J, /Q, /z are undefined or TBD 2 are reserved OF THE 94 Alternate Symbols. The following are available: Three undefined series \=, \Y, \Z can support 36 overlays Eight series \1 through \8 that can support 36 overlys each Three reserved series. ALTERNATE OVERLAYS: 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 need. The following tables will attempt to keep track of these and any other useful generic applications of overlay characters. POWER PLANT: #% /% = DX cluster C% = Coal G% = Geothermal H% = Hydroelectric N% = Nuclear S% = Solar T% = Turbine W% = Wind INCIDENT SITES: #' \' = Airplane Crash Site A' = Automobile crash site H' = Hazardous incident M' = Multi-Vehicle crash site P' = Pileup T' = Trunk wreck APRStt or DTMF gated users: #= M= = Mobile DTMF user H= = HT DTMF user Q= = QTH DTMF user E= = Echolink DTMF report I= = IRLP DTMF report R= = Repeater DTMF report E= = Event DTMF report etc HUMAN SYMBOL: #[ /[ = Human \[ = Wall Cloud (the original definition) S[ = Skier 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 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) NETWORK NODES: #8 88 = 802.11 network node (88) G8 = 802.11G (G8) HAZARDS: #H /H = hotel \H = Haze WH = Hazardous Waste RESTAURANTS: #R \R = Restaurant (generic) 7R = 7/11 KR = KFC MR = McDonalds, RADIOS and APRS DEVICES: #Y AY = Alinco IY = Icom KY = Kenwood YY = Yeasu/Standard GPS devices: #\ A\ = Avmap G5 ATM Machine or CURRENCY: #$ \$ = US dollars (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 Rc = RACES Sc = SATERN mobile canteen BUILDINGS: #h /h = Hospital \h = Ham Store Hh = Home Dept etc.. SPECIAL VEHICLES: #k /k = truck \k = SUV 4k = 4x4 Ak = ATV (all terrain vehicle) TRUCKS: #u /u = Truck (18 wheeler) 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: ******************************************************************** PROPOSAL TO ASSIGN MANY MORE BBLOCKS OF SYMBOL SETS April 2008 -------------------------------------------------------------------- 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 "DE" (a D overlay) will mean blowing Dust or sand "FE" (an F overlay) will mean Fog 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 "H`" (an H overlay) would mean Hail "D`" (an D overlay) would mean Drizzle "E`" (an E overlay) would mean slEEt "S`" (an S overlay) would mean Snow 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 "LI" (an L overlay) would mean Lightening 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 "W(" with W overlay would be a wall cloud "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 was only blowing snow #b was only blowing dust/sand #{ was only fog #* was snow only #: was hail only #D was drizzle only (could be used for DTMF users) #F was freezing rain only #e was sleet only #G was only Snow shower #J was only Lightening #p was only partly cloudy 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