Re: [gpsd-dev] implementing $GPVTG -- how should I interperet ', , , , ' fields?

[Gary E. Miller]

Yo teyrana!

On Wed, 16 May 2018 12:16:54 -0400
teyrana <address@hidden> wrote:

> Should empty fields (",," in NMEA 0183) be interpreted as missing, or
> zero?

Missing.

> I'm testing our $GPVTG patch, and it breaks 1 / 113 tests.

Pretty common for new patches.

> The line in question is near the top of
> 'test/daemon/gp-320fw-2019-04-07-coldboot.log.chk', at line 80:
> "$GPVTG,,T,,M,2C"  (Those double commas correspond to the velocity and
> course fields.)
> 
> So, this generates the line:
> '+{"class":"TPV","mode":2,"track":0.0000,"speed":0.000}'
> 
> While this is not very surprising...  is it expected / desired
> behavior?

Unwanted behavior.  No data is no data.  No data is not zero.

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

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