[Xastir-dev] Re: [Xastir] Is traffic encryption possible?

[Curt]

On Thu, 15 Nov 2007, Tapio Sokura wrote:

> I played around with the "spec" and xastir code and produced a patch against
> current CVS that implements receiving of !DAO!, both "human readable" and
> base91 variants. It's not perfect, but "works for me".

Thanks!  I've started looking at your tweaks, but if another
developer wants to take this on, fine by me, just let me know.


> IMO the biggest additional tweak the patch needs is changing of the white
> error box dimensions.

> Also different datums are accepted in input, but ignored in processing. The
> datum byte is returned by decode_dao(), but currently unused.

I'd like to fix these two things up eventually, but getting the
initial DAO patch into the code would be good.

The white error boxes are useful to see where a station _might_ be,
instead of where they're telling us they are.  Without the datum
conversions though we'd be reporting the position incorrectly, so we
might as well keep the larger error box until we are converting the
datums.

Second thought:  If the datum is reported as WGS84 we could reduce
the size of the error box 'cuz we wouldn't need to do a conversion.

What about NAD83?  I know that's very close to WGS84, but that's
only for NA right?  If someone on the other side of the world was
reporting NAD83 datum then the error between it and WGS84 could be
significant, right?  Is NAD83 available world-wide?  Could I be in
Japan or Europe and have a Garmin or Magellan GPS read out my
position in NAD83?

-- 
Curt, WE7U.				archer at eskimo dot com
http://www.eskimo.com/~archer
  Lotto:  A tax on people who are bad at math. - unknown
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