Re: [Jsbsim-devel] Field elevation, altitude ASL and altitude AGL

[Ron J. <wi...@je...>]

Hi Tony,

That's a good idea, but it raises a couple of questions:

- Do we leave the current <altitude> tag and behavior so as not to break
existing init files?

- How do we handle the case where <altitude-asl> is less than
<elevation>?

Thanks,
Ron

On Wed, 2009-08-05 at 09:18 -0700, Tony Peden wrote:
> I'd suggest that both inputs should be provided and both be labeled  
> ( asl and agl)
> 
> 
> --
> Tony
> Follow your heart, don't give up, and try like hell to not be stupid.
> 
> On Aug 5, 2009, at 9:09 AM, Ron Jensen <wi...@je...> wrote:
> 
> > On Wed, 2009-08-05 at 16:32 +0200, Fabian Grodek wrote:
> >> Hello,
> >> It seems there's still something broken in the field elevation and
> >> flight altitude issue.
> >>
> >> If in the init file I set :
> >>  <elevation unit="FT">   5,000  </elevation>
> >>  <altitude unit="FT">    15,000  </altitude>
> >>
> >> In the output I get:
> >>   Altitude ASL = 20,000 ft, while  Altitude AGL = 15,000 ft.
> >>
> >> I would expect:
> >>   Altitude ASL = 15000 ft, and Altitude AGL = 15,000 - 5,000 =
> >> 10,000 ft.
> >>
> >> The property "position/terrain-elevation-asl-ft" correctly reports
> >> 5,000 ft.
> >>
> >> Fabian
> >
> >
> >  It looks to me like <altitude unit="FT"> is AGL not ASL.
> >
> > Altitude ASL = 15,000 + 5,000.
> >
> >  Whether that is the desired input is open to debate.
> >
> > (pro current behavior side)
> >  It prevents rewriting both properties in an init file when changing
> > the ground elevation, which is a good thing since the elevation
> > parameter was put in to test take-off/landings. By that I mean the AGL
> > behavior allows <altitude> to be a constant in an init file that  
> > starts
> > on the ground.  The AGL behavior also allows  <altitude> to be a
> > constant if the init file sets up an approach position. If you want
> > <altitude> to be from sea level either leave the <elevation> tag out  
> > or
> > explicitly set it to 0.
> >
> > (con current behavior side)
> >  Having <altitude> in AGL is somewhat confusing.
> >
> > Thanks,
> >
> > Ron
> >
> >
> >
> >
> >
> > --- 
> > --- 
> > --- 
> > ---------------------------------------------------------------------
> > Let Crystal Reports handle the reporting - Free Crystal Reports 2008  
> > 30-Day
> > trial. Simplify your report design, integration and deployment - and  
> > focus on
> > what you do best, core application coding. Discover what's new with
> > Crystal Reports now.  http://p.sf.net/sfu/bobj-july
> > _______________________________________________
> > Jsbsim-devel mailing list
> > Jsb...@li...
> > https://lists.sourceforge.net/lists/listinfo/jsbsim-devel
> > _______________________________________________
> > The JSBSim Flight Dynamics Model project
> > http://www.JSBSim.org
> > _______________________________________________
> >
> 
> ------------------------------------------------------------------------------
> Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day 
> trial. Simplify your report design, integration and deployment - and focus on 
> what you do best, core application coding. Discover what's new with 
> Crystal Reports now.  http://p.sf.net/sfu/bobj-july
> _______________________________________________
> Jsbsim-devel mailing list
> Jsb...@li...
> https://lists.sourceforge.net/lists/listinfo/jsbsim-devel
> _______________________________________________
> The JSBSim Flight Dynamics Model project
> http://www.JSBSim.org
> _______________________________________________
>