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.
>>
>>
>
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