[aprssig] Vicinity Plots on APRS

Bob Bruninga bruninga at usna.edu
Wed Jun 1 14:29:06 EDT 2011

> a few years ago my wife drove to Florida...
> Early in the trip the GPS became disconnected. 
> FindU was therefore showing her off the West Coast of Africa.  
> However, by looking at the Digi... I could look that 
> station up and see where she was on her trip, 
> down to at least the city/county level. 

Actually, I think Steve finally added VICINITY to FINDU that will do that
automatically, but I have never been able to find any info about the
capability on his pages.  Even search for "vicinity" on any of his pages
finds nothing.  I think you add &vicinity=1 to the URL.

Yes, just tried it, and it finds the nearest digi, but the map display is

> Given the odds against a station actually being at 0 Lat/0 Long, 
> should there be a rule to the effect that those positions 
> will be treated as position-less and therefore plotted using 
> the Vicinity protocol? Perhaps a user option? 

I agree.  That was in the fundamental concept of APRS.  There is another
similar feature in APRSdos that used LAT/LONG of 40/40  (out in the ocean)
as a means of reporting position from a table.  This way, one could just
enter a LAT of 4013 and that would mean you were at checkpoint 13, and then
that woiuld be associated ffom a lookup table for that checkpoint.
Something like that...

That made it easy to use D7's without fussing with GPS's for special events
but could still generally see where operators were.

> Or is that already covered in the spec?

Not allowed by the other authors on the SPEC committee who did not want to
be told how to plot things.

Bob, Wb4APR



-----Original Message-----
>From: Bob Bruninga <bruninga at usna.edu>
>> Just imagine if you lived in West Africa and ran this programe
>> how annoying it would be having all these stations just off the
>> coast at 0 Lat 0 Long coming and going .
>Yes, that was never intended to happen...
>> Why display a station anywhere on a map when it's a guess.
>Because the global APRS system is a big place.  But knowing someone
>originated a packet via a given digi, nails down the stations position in
>the network (for communications purposes) 99.99999% from about 6 million to

Randy Allen, KA0AZS

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