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[aprssig] findu.com Location off by 100 miles.

Robert Bruninga bruninga at usna.edu
Mon Jun 5 15:00:48 UTC 2006


>> In the original APRS, depending on map Range Scale, a SYMBOL
>> is shown if the "size" of the symbol is larger than the area of
>> ambiguity.  But if the viewer zooms in below that point, then
>> the symbol is replaced with a CIRCLE showing the size of the
>> ambiguity.  Thus, there is never any confusion on the part
>> of the viewer as to what he is seeing and he will NEVER see
>> a symbol in the wrong position.
>
>I'd say displaying a circle is also improper - it is a rectangular  
>area...

Ah, but again that interpretation is not interpreting the sender's
intent.  Position ambiguity means the sender is only sure of his
position to some level of accuracy.  If he uses 1 mile ambiguity
then it does not make sense to try to force precise "edges" of that
unknown quantity to something too precise. 

THe circle simply communicates that the position is unknown
below that resolution.  A square would be fine too, but both
should not be interpreted as precise lines'in-th-sand...

de Wb4APR, Bob






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