[aprssig] Vicinity Plots on APRS

[Bob Bruninga]

> 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
broken.

> 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



73

Randy

-----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
>1.


Randy Allen, KA0AZS


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