Re: Gama usage question

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Greg, your answer is 100% perfect, I cannot add anything more.
Ales

On 5 December 2012 15:12, Greg Troxel <[email protected]> wrote:

>
>   I have a large point-cloud. I would like to convert coordinate
>   systems, a 7-DOF rotate, translate, and scale.
>
> My quick reaction is that gama isn't the right tool, since it's about
> estimating coordinates given observations.  If you already have an
> internally-consistent point cloud, then you aren't estimating
> coordinates.
>
> I think your problem has two sub-parts:
>
>   estimating the rotation/translation/scale
>
>   applying it
>
> Applying it is similar to datum transformation, except that datum
> transformations are typically small angles.
>
> It may be that part of the gama code is helpful.
>
> Given only two control points, I would think you could
>
>   transform the control points real coordintes to ECEF XYZ (via proj4)
>
>   compute translation, scale
>
>   compute/choose an orientation, because you're down a control point
>
> pretty easily, with the last two steps being done with a calculator
> even.
>
> Then, you could end up with rotate and translate matrices, and apply
> them with octave.
>
>
> If you had more control points, you'd be in a least-squares situation
> (and better off data wise with a harder processing problem, really :-).
>
> It may be that having framed the problem of multiple control points with
> coordinates in two different systems, you can write code to use the
> solver in gama to solve that different problem.  But I'd expect the bulk
> of gama to be about computing the partial derivatives of the types of
> observations used in surveying.
>
> _______________________________________________
> Info-gama mailing list
> [email protected]
> https://lists.gnu.org/mailman/listinfo/info-gama
>
>

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Greg, your answer is 100% perfect, I cannot add anything more.<div>Ales<br>=
<br><div class=3D"gmail_quote">On 5 December 2012 15:12, Greg Troxel <span =
dir=3D"ltr">&lt;<a href=3D"mailto:[email protected]" target=3D"_blank">gd=
[email protected]</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><div class=3D"im"><br>
=C2=A0 I have a large point-cloud. I would like to convert coordinate<br>
=C2=A0 systems, a 7-DOF rotate, translate, and scale.<br>
<br>
</div>My quick reaction is that gama isn&#39;t the right tool, since it&#39=
;s about<br>
estimating coordinates given observations. =C2=A0If you already have an<br>
internally-consistent point cloud, then you aren&#39;t estimating<br>
coordinates.<br>
<br>
I think your problem has two sub-parts:<br>
<br>
=C2=A0 estimating the rotation/translation/scale<br>
<br>
=C2=A0 applying it<br>
<br>
Applying it is similar to datum transformation, except that datum<br>
transformations are typically small angles.<br>
<br>
It may be that part of the gama code is helpful.<br>
<br>
Given only two control points, I would think you could<br>
<br>
=C2=A0 transform the control points real coordintes to ECEF XYZ (via proj4)=
<br>
<br>
=C2=A0 compute translation, scale<br>
<br>
=C2=A0 compute/choose an orientation, because you&#39;re down a control poi=
nt<br>
<br>
pretty easily, with the last two steps being done with a calculator<br>
even.<br>
<br>
Then, you could end up with rotate and translate matrices, and apply<br>
them with octave.<br>
<br>
<br>
If you had more control points, you&#39;d be in a least-squares situation<b=
r>
(and better off data wise with a harder processing problem, really :-).<br>
<br>
It may be that having framed the problem of multiple control points with<br=
>
coordinates in two different systems, you can write code to use the<br>
solver in gama to solve that different problem. =C2=A0But I&#39;d expect th=
e bulk<br>
of gama to be about computing the partial derivatives of the types of<br>
observations used in surveying.<br>
<br>_______________________________________________<br>
Info-gama mailing list<br>
<a href=3D"mailto:[email protected]">[email protected]</a><br>
<a href=3D"https://lists.gnu.org/mailman/listinfo/info-gama" target=3D"_bla=
nk">https://lists.gnu.org/mailman/listinfo/info-gama</a><br>
<br></blockquote></div><br></div>

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