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[aprssig] Vicinity plotting

Bob Bruninga bruninga at usna.edu
Tue Nov 22 22:05:29 UTC 2011


I guess I have to disagree.

> Having struggled with the same thing myself, I finally 
> decided that any station from which I have not received 
> a position report will be located at 0,0 until I get a position report.

> I examined many many paths before coming to the conclusion that 
> there is NO good solution that will RELIABLY tell you where you 
> should RANDOMLY position said station.  

But the vast majority can be inferred and they should be.  If there are
troublesome paths, then drop those... and only those.  Preserve the best
information you have, don't throw it away with a meaningless placement near
Africa.

> And cluttering the map with ambiguity circles or any other indication 
> that the station really is NOT where you're drawing it was worse 
> than just keeping the station off the map until a position was received.

Depends on y9our definition of "worse".  We are not after pretty maps here.
We are after the best presentation of the information we are given.  If we
know a new station was heard by DIGI1, and still do not have a position on
them, then they should be placed in the system with a vicinity position
around that digi.

APRS is a communication network, not a MAP.  Displaying our best information
about the station is the goal.  And displaying a visinty plot is the best we
can do until we get a posit.  The answer of 0,0 is not our best info...

> If you haven't heard where a station is, then my opinion 
> is that the station might as well be invisible, 

This is the wrong map-centric view of APRS.  APRS is NOT A MAP system.  It
is a communication system.  If you receive a packet from someone, then you
have lots of information about that station.  And in most cases the path
tells you a lot about what you need to communicate.  NOT THE MAP.

> but at least I draw them at 0,0 off the coast of Africa.

But that is a *wrong* network view.  It violates the integrity of APRS as an
information resource.  That iw why se defined the vicinity plot.

Bob, WB4APR




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