[aprssig] APRS LAT/LONG standards

Robert Bruninga bruninga at usna.edu
Thu May 26 18:57:57 EDT 2005

>>> steve at dimse.com 5/26/2005 4:19:39 PM >>>
>Why do you feel that the way you do things is 
>the way the rest of the   world does things?

Because it is the way Navigation is done before
programmers started taking shortcuts.

>Curt has already pointed out aircraft use decimal 

But he is wrong.  Every pilot and Naval Avaiator
here in the Aerospace Departement and every
naval officer fully qualified in Navigation says so.

>APRSworld uses decimal degrees.

Programmer output.

>APRS+SA uses decimal degrees.

Programmer output.

>Steet Atlas uses decimal degrees.

Programmer output to the mass consumer

>Chicago Mapping uses decimal degrees.

Programmer output to the mass consumer

>MapBlast uses decimal degrees:

Programmer output to the masses with web browsers.

>Topozone uses decimal degrees

That is a URL, a programmers simplificaiton for machine
comunication. not the way navigators do it.

>Acme mapper uses decimal degrees


Again, a programmers shortcut for eacy machine use. 
Of course, everything uses decimal degrees internally,
but that is NOT the way navigation is done and is NOT 
the standard human interrface.  Thought it may become 
so as button pushers takeover the world.

>I do not know of a single internet service that
> uses degrees/minutes.

What do you mean by "uses"????  You are
too focused on what goes on inside the
machine and in URL's and in machine speak.
But ANYONE who uses LAT/LONG professionally
in relation to the real world and charts
knows that decimal degrees is just a 
programmers simplification.  The standard is
Degrrees and decimal minutes.

Go "use" your web-based decimal degrees on
a chart.  Or look up an Airport LAT/LONG whie
flying, or a VOR or TACCAN coordinates while
flying.  Are you saying that you feel cofortable
with pilots using calculators or WEB browsers
while flying to convert from the programmers
outputs to their nautical charts??

>DD MM SS is a relic of a much earlier time, 

Agreed.  It is obsolete since 1984 when the GPS
standards began to come out.  No one but
WinAPRS uses it anymore...

> From a  computer point of view..., decimal 
>degrees convey  more precision in the same 
>number of characters, and all calculations  
>involving lat/lon are much easier after they 
>are converted to decimal.

Absolutely!  I agree 100%, but again, you are
talking like a programmer.  Decimal degrees should
stay INSIDE the computer and programmers
take the effort to present the result to the human
user in the standard classic navigation standard for 
LAT/LONG which is degrees and decimal minutes.

>So just because you disagree, do not put the 
>blame on me. The rest of  the world is (gradually) 
>adopting a standard that simply makes more  

Makes more sense to progrmmers but makes no sense
to navigators and the way it has always been.  Most
people dont care because it is just numbers anyway.
But that is exactly why we have all these conversion
problems when joe-HAM uses decimal degrees and
he is talking to a professional pilot or navigator or
established system that uses LAT/LONG.

> I'm pretty sure decimal has been around longer 
>than any of us have been alive ;-)

absolutely wrong.  Columbus used degrees and
minutes (and seconds) so has all navigation until
the arrival of the button pushers.  It was only
with the arrival of the GPS back in 1984 (or so)
that they made a big effort to get rid of
seconds and standardize on DEG and decimal 
minutes.  (thank goodness).

And because of that GPS standard, and the 
entire re-alignment of all navigation systems
to use degreees and decimal minutes over the
last 20 years is also why from the beginning,
the APRS standard was also degrees and
decimal minutes.  

But then the programs started taking the easy
way and displaying easy decimal degrees becasue
they simply were not familiar with classic navigation
and other pre-programmer existing systems.

But as  you say, programmers rule. But your
argument that you do it becuse all the other
progarmmers do it is entirely circular reasoning.


More information about the aprssig mailing list