[ gpsdrive ] libgps

[Guenther Meyer]

Am Montag 29 Dezember 2008 schrieb Hamish:
> > > or maybe better: we set it depending on the travel mode:
> > > "track" for plane and boat, "heading" for all the others?
>
> No! definition is the same regardless of mode of travel.
> otherwise you just propagate the confusion.
>
ok.

> > "Track" is where you've been, allowing for leeway, tide etc. " hdg" is
> > just where you are pointing.
>
> the two words to be used should be "bearing" vs "heading"
> see the NMEA faq in Documentation/ for usage
>
> often course-over-ground (COG) is used to make it east to tell which one
> you are talking about.
>
> fwiw we've got a GPS compass that shows ship's aspect independent of ship's
> COG. 2 gps antennas about 20cm appart, it works on phase difference I
> think.
>
most people won't have a gps device, that can detect the real heading I guess, 
gpsd also only gets the 'track' direction afaik.
and, the difference between 'heading' and 'track' is only relevant on boats 
and planes, which may be a smaller group of users than the ones driving cars 
or similar vehicles; but they are also targeted by gpsdrive...

so what to do?

'track' is a term many can't do anything with.
'heading' is something everyone should understand, but it is not correct in 
some scenarios.


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