Re: course of AIS targets

[Gary E. Miller]

Yo Владимир!

On Sat, 20 May 2023 12:06:35 +0300
Владимир Калачихин <v.kalachikhin@gmail.com> wrote:

> 20.05.2023 01:16, Gary E. Miller пишет:
> > Since JSON has no "null" value, and numerics must be numeric, it is
> > normal to follow the spec and use 360.0 as "not available".
> > Exactly as the spec says to do.  
> 
> Spec says about 3600...
> Ok, but for speed gpsd use 'nan' instead 1023, and for ROT - 'nan' 
> instead 128.

JSON has no way to send NaN (or null) in a numeric.  Nor does AIS, thus
the 3600.

> > If you prefer, since the COG is "not available", I could change
> > gpsd_json.c sp that when 360.0 == COG, to not output the field at
> > all.  Would you prefer that.  
> 
> Yes.

I'm not sure what clients that may break.  The only benefit is maybe
better style.  Balancing maringal gains versus actual harm to existing
clients:  I'll leave it.

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        gem@rellim.com  Tel:+1 541 382 8588

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    "If you can't measure it, you can't improve it." - Lord Kelvin

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