[aprssig] APRS LAT/LONG standards

Curt, WE7U archer at eskimo.com
Fri May 27 15:47:18 EDT 2005

On Thu, 26 May 2005, Robert Bruninga wrote:

> Which is one of the biggest problems in APRS.
> There is no classical navigation system that uses
> decimal degrees for navigation.  ANd it is not
> the APRS standard, nor the GPS standar and it
> only causes these kinds of problems.
> Why do you feel it is important to be out of step
> with the rest of the GPS world, APRS and all other
> classic systems of navigation?

I almost hate to bring this up, but I will anyway:  While looking
around a bit for the aviation-GPS standard, I happened up on this
(which has little to do with aviation, but a lot to do with this

  GPS For Disaster Operations
  <http://www.training.fema.gov/emiweb/downloads/DF109 GPS IG.pdf>

FEMA uses decimal degrees, in NAD83 or WGS84 datum.  The reason they
give for the decimal degrees is on page 39:

  "Several different formats exist.  FEMA uses the format most
  common for input into GIS software, which is the Degrees Decimal

Considering that they often deal in large areas I can see their
reasoning.  For smaller land-based areas like we do in SAR, UTM or
MGRS (basically equivalent) as a standard would make more sense.

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

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