[aprssig] Symbols for traffic alerts

Steve AB3LT at RoseAndSteve.us
Sat Nov 12 09:26:31 CST 2011

Thanks for you comments. I've been running a PSGATE here 24/7 for
about two years. The most useful thing I've found is that I can't just
sit in the shack and let the computer do its thing, squirting out APRS
Objects. I set it up, got it running, then I'll throw a laptop with
xastir in the truck and drive around my county and see what works. Get
home, think about things, read through mailing lists like aprssig,
tweak some settings like adding object location specific outgoing
paths, like you mention below, and go out again and see if or how it
works. I challenge anyone who says HAM's have nowhere to experiment on
VHF to jump in and give APRS a hard look beyond just connecting to
APRS-IS over the internet and plotting symbols on a map. There is so
much more to it!
73, Steve AB3LT

On Fri, Nov 11, 2011 at 9:50 PM, Bob Bruninga <bruninga at usna.edu> wrote:
> This is an Excellent use of APRS!
> My version of APRStfc back a decade ago suffered from a lack of source data... now it is great to see this new capability!
> Some thoughts, probably not relevant... but :
> 1) Remember the Speed Post symbol that is supposed to show on the map with the actual speed ON the sign symbol showing speed past that point.   Probably not of value in incidents and for mobiles with no client maps.  And most clients didnt implement it anyway.
> 2) It is paramount that these objects be optimized for the APRS mobile (D7,D700,D710,FTM350 and VX8 and other hardware displays) even at the expense of other viewers.  All other systems have their own internet access..
> 3) Every effort should be made to inject these ONLY within the range of the actual event.  This takes a lot of work, but will pay off by preventing this from being viewed as SPAM.  THis is an interesting challenge, depending on the degree atempted.  As a first order it is simply:
> a) Having a list of all digis this information server can hit DIRECT.  And computing the PHG mobile range of these digis.
> b) Comparing the position of any such object to the closest digi (and PHG range)
> c) then using only that digi as the path.
> Any path that needs TWO hops to hit should probably not be on APRS as it covers far too much area.  And out-of-area-alerts turn people off or make them soon ignore them to the degree that they then ignore the rare one that DOES apply to them.
> But I can see that if DIRECTED paths using explicit digis hops were used, and the server was serving a larger rural area, then I woiuld not object to an explicit 2 hop path.
> There is almost an order of magnitude difference in QRM between a 2 hop WIDE2-2 (which can hit a dozen digis or more) and a 2 hop explicit path that only hits 2.
> Now if this code can be made easily transportable, then the ideal use of it is to distribute it to key hams in the state that can source it direct 1 hop to the needed widely distributed digis.
> Keep up the great work!
> Bob, WB4APR
> ---- Original message ----
>>Date: Fri, 11 Nov 2011 15:14:14 -0500
>>From: aprssig-bounces at tapr.org (on behalf of Steve <AB3LT at roseandsteve.us>)
>>Subject: Re: [aprssig] Symbols for traffic alerts
>>To: TAPR APRS Mailing List <aprssig at tapr.org>
>>Here are the symbols I use for objects in my area:
>>any other EMS "/a"
>>any other Fire "/f"
>>any other Traffic "/P"
>>The Objects have a object id in the format "EMS XXXX", "FIRE XXXX", or
>>"TFX XXXXX"  where XXXX is the base36 encoded incident number. I
>>uppercase and use the incident type and subtype as the object comment
>>text. If the incident is along a major roadway  (state route, highway,
>>turnpike) I add an abbreviated version of the road followed by either
>>a single pipe | if the incident affects only one lane/direction,
>>double pipe || otherwise denotes that both lanes/directions are
>>I have a self adjusting net cycle time which retransmits still active
>>incidents about every 20 minutes. this self-adjusts if there are a lot
>>of incidents like during a blizzard, but it stays mostly at 20 minutes
>>the rest of the time.
>>I send these objects out with a path including  RFONLY,NOGATE and tag
>>them with the !x! no-archive flag because I reckon that if someone has
>>an internet connection to receive APRS-IS then they also have an
>>internet connection to traffic.com or any of the other sources for
>>traffic/incident information, and they don't need to get this from the
>>aprs-is backbone, unlike most stations on RF.
>>When sending object kill messages I replace the last part of the
>>object comment text with (CLEARED) so that text-only displays like the
>>hamhud and D700 users can see that the incident has ended.
>>I populate the Object's timestamp with the dispatch time of the
>>incident, comparing it to when you received the object you can
>>calculate how long the incident has been active.
>>here's an example:
>>6USLF*021347z4001.50NI07513.70W'I76 || VEHICLE ACCIDENT INJURIES
>> !x!
>>6USLF_021347z4001.50NI07513.70W'I76 || VEHICLE ACCIDENT
>>hope this helps and 73,
>>Steve AB3LT
>>On Fri, Nov 11, 2011 at 3:43 AM, Morten Johansen <morten at bzzt.no> wrote:
>>> Hi, list!
>>> I've been following the list for a while, but this is my first post. I hope this is the right place to post this question.
>>> The Norwegian Road Authorities are kind enough to post traffic alerts in XML format including geographic position, urgency information and other "snacks".
>>> For some months now I've run an experiment that analyzes these alerts for my area and injects them into the APRS-IS as objects.
>>> There has been lots of feedback, and all interested parties (including NRRL) have been rounded up in a mailing list to try to outline a permanent service.
>>> Alerts have a "type", of which the most common are: "closed road", "temporarily closed road" or "reduced navigability road". It basically describes the impact of the alert for traffic.
>>> The majority of the alerts come from road work, and because of this the \j Work Zone symbol is used by default.
>>> Our question to this list is what APRS symbols we should use for these situations:
>>> * Closed road
>>> * Traffic incident - \' ? We have no way of knowing if it's a car, truck or whether there are several involved. Looking for a general traffic incident symbol.
>>> We also would like some opinions on which symbol should have precedent in case of "closed road" because of "traffic incident".
>>> Should the "closed road" symbol be used always for consistency?
>>> Should the "traffic incident" symbol be used to provide information granularity?
>>> The object text will contain a short description of the situation in any case.
>>> de Morten LA1FTA
>>> _______________________________________________
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>>> aprssig at tapr.org
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