I have just sent you a demo key for Global Mapper v11.



The projection of a point from a start point and a bearing hasn't changed
(that was a completely separate algorithm). What has changed is the
calculation of the bearing between two points. So if you measure the bearing
between two points it will now use the Vincenty algorithm for the best
accuracy.



Thanks,



Mike

Global Mapper Support

support@...



From: global_mapper@yahoogroups.com [mailto:global_mapper@yahoogroups.com]
On Behalf Of planes54
Sent: Wednesday, July 15, 2009 5:29 PM
To: global_mapper@yahoogroups.com
Subject: [global_mapper] Re: ITRF 2000 datums






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 <mailto:global_mapper%40yahoogroups.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%40yahoogroups.com>
[mailto:global_mapper@yahoogroups.com
<mailto:global_mapper%40yahoogroups.com> ]
> On Behalf Of planes54
> Sent: Saturday, July 11, 2009 9:27 PM
> To: global_mapper@yahoogroups.com <mailto:global_mapper%40yahoogroups.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>
> <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%40yahoogroups.com>
> [mailto:global_mapper@yahoogroups.com
<mailto:global_mapper%40yahoogroups.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>
<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]
>





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