[ gpsdrive ] libgps

[Joerg Ostertag (gpsdrive Tettnang/Germany)]

Hi,

Could you please add this explenation to the Gpsdrive-FAQ.

Thanks


On Donnerstag 25 Dezember 2008, Jan-Benedict Glaw wrote:
> On Wed, 2008-12-24 17:43:02 +0100, Guenther Meyer <d.s.e at sordidmusic.com> 
wrote:
> > Am Mittwoch 24 Dezember 2008 schrieb Jan-Benedict Glaw:
> > > > Heading: %.2f\n  Time: %s\n", data->fix.track,utctime);
> > >
> > > This is track direction, not heading.
> >
> > and this is not the same?
>
> Not neccessarily. For a /car/, this is usually the same, because it
> uses a static reference system (earth) for itself. However, the same
> is not true for eg. planes or ships, because wind / water will move,
> too.
>
> Consider a river, flowing from north to south. Think of yourself
> sitting in a very small boat, strictly /heading/ into west direction.
> Your /track/ however is in south-west direction, because the flowing
> water forces you southwards.
>
> With some GPS receivers reporting track (from GPS) as well as heading
> (from eg. a fluxgate compass), you can even have a changing heading
> while staying at the very same position within your track.
>
> So this is a wording issue. "Heading" is where you would go without
> other forces, "track" is where you actually move to (due to outer
> powers applied to you, usually outside of your control).
>
> MfG, JBG



-- 

Jörg (Germany, Tettnang)

http://www.ostertag.name/