Re: Gama usage question
Aleš Čepek <[email protected]> Wed, 5 Dec 2012 22:05:19 +0100
| Newsgroups | gmane.comp.gnu.gama.announce |
|---|---|
| Message-ID | <CAGN9seT12QSgsVN9kD8OtuAutj=+3F3N-tV6c=PDEtbzk-5yTg@mail.gmail.com> |
--===============2895766682965398632== Content-Type: multipart/alternative; boundary=14dae9340af308cad604d0215763 --14dae9340af308cad604d0215763 Content-Type: text/plain; charset=UTF-8 I am sorry to say, that Greg is right. Gama is design for a different role. Ales On 5 December 2012 19:34, Ken Mankoff <[email protected]> wrote: > Hi Greg, > > I think you are right it isn't the right tool. Everything is constrained > in my data, I just want to 1) determine and 2) apply a 7 DOF operation (3 > translate, 3 rotate, 1 scale). I was hoping Gama might help with that. > > Thanks, > > -k. > > > On Wed, 5 Dec 2012, Greg Troxel 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<https://lists.gnu.org/mailman/listinfo/info-gama> > --14dae9340af308cad604d0215763 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable I am sorry to say, that Greg is right. Gama is design for a different role.= <div>Ales<br><br><div class=3D"gmail_quote">On 5 December 2012 19:34, Ken M= ankoff <span dir=3D"ltr"><<a href=3D"mailto:[email protected]" target=3D= "_blank">[email protected]</a>></span> wrote:<br> <blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p= x #ccc solid;padding-left:1ex">Hi Greg,<br> <br> I think you are right it isn't the right tool. Everything is constraine= d in my data, I just want to 1) determine and 2) apply a 7 DOF operation (3= translate, 3 rotate, 1 scale). I was hoping Gama might help with that.<br> <br> Thanks,<br> <br> =C2=A0 -k.<div class=3D"HOEnZb"><div class=3D"h5"><br> <br> On Wed, 5 Dec 2012, Greg Troxel wrote:<br> <br> <blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p= x #ccc solid;padding-left:1ex"> <br> =C2=A0I have a large point-cloud. I would like to convert coordinate<br> =C2=A0systems, a 7-DOF rotate, translate, and scale.<br> <br> My quick reaction is that gama isn't the right tool, since it's abo= ut<br> estimating coordinates given observations. =C2=A0If you already have an<br> internally-consistent point cloud, then you aren't estimating<br> coordinates.<br> <br> I think your problem has two sub-parts:<br> <br> =C2=A0estimating the rotation/translation/scale<br> <br> =C2=A0applying 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=A0transform the control points real coordintes to ECEF XYZ (via proj4)<= br> <br> =C2=A0compute translation, scale<br> <br> =C2=A0compute/choose an orientation, because you're down a control poin= t<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'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'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> </blockquote> <br> <br></div></div><div class=3D"HOEnZb"><div class=3D"h5"> ______________________________<u></u>_________________<br> Info-gama mailing list<br> <a href=3D"mailto:[email protected]" target=3D"_blank">[email protected]</a= ><br> <a href=3D"https://lists.gnu.org/mailman/listinfo/info-gama" target=3D"_bla= nk">https://lists.gnu.org/mailman/<u></u>listinfo/info-gama</a><br> </div></div></blockquote></div><br></div> --14dae9340af308cad604d0215763-- --===============2895766682965398632== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Info-gama mailing list [email protected] https://lists.gnu.org/mailman/listinfo/info-gama --===============2895766682965398632==--