Mike

Thanks for that, I would like to try this V11 beta

I am mainly working in Auto steer with Precision Ag Customers they we having
problems in setting lines in machines to follow Rows already created on the
ground.

I had identerfied the problem which was caused by the process they were using to
set the lines . What is was attempting to do was to Graphicly ilerstrate how
they had created the error.

What i noticed was that when I created the heading in GM it was creating a
heading with a different value to that displayed on the GPS

I asume now if we enter a new line using the Point A and the heading that the
lines should be on top of each other.

Thanks
Planes54





-- In global_mapper@yahoogroups.com, "Global Mapper Support" <global_mapper@...>
wrote:
>
> I was able to update the bearing calculation in Global Mapper using the
> Vincenty Formula (this was already used for distance, so I just had to
> extract the bearing as well). Now I get a bearing of 231 36 55.6, which is
> very close to what the Geoscience Australia web site displays.
>
>
>
> If you want to use the v11 beta I can provide you with a new build with this
> change.
>
>
>
> Thanks,
>
>
>
> Mike
>
> Global Mapper Support
>
> support@...
>
>
>
> From: global_mapper@yahoogroups.com [mailto:global_mapper@yahoogroups.com]
> On Behalf Of planes54
> Sent: Saturday, July 11, 2009 9:27 PM
> To: global_mapper@yahoogroups.com
> Subject: [global_mapper] Re: ITRF 2000 datums
>
>
>
>
>
>
>
>
> I dont think it is a differance between true and magnatic I have carried out
> some checking and I think it is the way GM 10.2 calculates the heading.
> I have checked the heading between the two point using the Vincenty's
> Formulae, Inverse method on the Geosience Australia web site and it produced
> a heading 231 36 55.11 which is very close to the 231.6 that the GPS system
> produced. The current magnatic var at this location is around 9.4 GM 10.2 is
> displaying a difference in the order of 10deg.
>
> The reason I was using GM10.2 is to graphicly display the guidance lines
> collected in the GPS system and to show the differences in the lines over
> 4-6km
>
> Is it possiable to see if the generated heading can be corrected
>
> Thanks
>
> --- In global_mapper@yahoogroups.com
> <mailto:global_mapper%40yahoogroups.com> , "Global Mapper Support"
> <global_mapper@> wrote:
> >
> > How close are your points together? I wouldn't expect any significant
> > difference in bearing between points just based on a datum difference.
> > Typically ITRF 2000 is quite close to WGS84 and doesn't represent any
> > significant shift in orientation. Perhaps the heading difference you are
> > seeing is a True North vs. Magnetic North difference?
> >
> >
> >
> > Thanks,
> >
> >
> >
> > Mike
> >
> > Global Mapper Support
> >
> > support@
> >
> >
> >
> > From: global_mapper@yahoogroups.com
> <mailto:global_mapper%40yahoogroups.com>
> [mailto:global_mapper@yahoogroups.com
> <mailto:global_mapper%40yahoogroups.com> ]
> > On Behalf Of planes54
> > Sent: Tuesday, July 07, 2009 11:22 PM
> > To: global_mapper@yahoogroups.com <mailto:global_mapper%40yahoogroups.com>
>
> > Subject: [global_mapper] ITRF 2000 datums
> >
> >
> >
> >
> >
> >
> >
> >
> > Is it possiable to set ITRF 2000 up as a datum in GM 10.2 I am having a
> > problem when I enter Point A and point B using the WGS84 datum getting the
> > correct heading as I beleive the Point cordernats were gererated using the
> > ITRF 2000 datum
> > Can any one assist with the data necessary to set up this datum
> >
> > Thanks
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>
>
>
>
> [Non-text portions of this message have been removed]
>