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[aprssig] The best resolution of position from APRS

Curt, WE7U archer at eskimo.com
Tue Jan 3 22:42:03 UTC 2006


On Tue, 3 Jan 2006, Robert Bruninga wrote:

> That was 8 years ago.  Then 7 years ago, we found
> out it that compressed OBJECTS were not used at
> the time AND incompatible with the Kenwoods.  Since
> then, for the last 6 years I have asked for everyone
> to not use the compressed object format and it
> was obsoleted in the APRS11 adendum.

This was a contested matter during that entire time as I recall.

The 1.1 web page says: "Call for Vote 30 July 2004".  Was it voted
on and ratified?  Is there a static PDF of the ratified 1.1
spec, or only the web pages that may be modified at any time?  In
other words, how static is the 1.1 spec?

I don't recall any of the Xastir development team being involved
even though it was one of the prominent apps during the time (and
still is).  Who was involved in the process?


> Pleaser read my line 1 again.  I said the compressed
> OBJECT Format is obsolete, I did not say the
> compressed position format is obsolete.

I find this deprecation of compressed objects/items unacceptable.

If I'm at SAR base placing objects on a map and have only 60'
resolution for this placement, I cannot place them where needed at
times.  We sometimes work with small search areas or with major
obstructions like rivers/cliffs very close to where an object needs
to be placed.  If the object then jumps across to the other side of
a cliff/river from where it was placed (due to the limited
resolution) and this is not immediately noticed, it can cause major
problems for the searchers who might need to get to that spot later.
If working with a small search area and I can't place the object
even _in_ the search area, that's a major problem.

As compressed objects/items were in the spec from day one until at
least July 2004, and since the most popular APRS clients support it
but don't support the newer high-res addition to the spec (plus we
don't use Kenwoods much in our county's SAR), I see compelling
reasons to use compressed objects/items in order to take advantage
of the needed resolution.

Once we implement the new high-res spec-ok'ed method in Xastir I'd
probably still tend to use Base-91 Compressed objects/items due to
the number of people using UI-View32 in our area who wouldn't have
access to the new method.

Yes, there's a conflict between me screaming about Kenwoods not
being upgradeable and me _not_ screaming about UI-View32 problems:
There's not a whole lot anyone can do about UI-View32 except replace
things via the plug-in API, which will only go so far.  I admit I'm
not sure where that line is as I don't program for that API.

--
Curt, WE7U.   APRS Client Comparisons: http://www.eskimo.com/~archer
"Lotto:    A tax on people who are bad at math." -- unknown
"Windows:  Microsoft's tax on computer illiterates." -- WE7U
"The world DOES revolve around me:  I picked the coordinate system!"




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