Transformation of rotation

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Transformation of rotation

phdr_hroch

Hi I want to transform rotation in XY (one angle) from one coordinate system to another (JTSK -> WGS84). I'm want to transform text, defined by origin, scale and rotation (angle around z axis). Transfrom scale from one system to another is not a problem, but how can I transform rotation. I know that transformation includes different projections, so its not going to be accurate (i would have to transform text definitions too). But partial solution is fine.

Filip


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Re: Transformation of rotation

support.mn
Hello,

use 7 parameter datum shift - that include rotational parameters for each axis

in proj.4 you use towgs84 statement to define any datum shift.

see also:

http://en.wikipedia.org/wiki/Helmert_transformation

Janne.

----------------------------------------------------------------------------------------------

Filip Arlet [[hidden email]] kirjoitti:

>
> Hi I want to transform rotation in XY (one angle) from one coordinate system
> to another (JTSK -> WGS84). I'm want to transform text, defined by origin,
> scale and rotation (angle around z axis). Transfrom scale from one system to
> another is not a problem, but how can I transform rotation. I know that
> transformation includes different projections, so its not going to be
> accurate (i would have to transform text definitions too). But partial
> solution is fine.
>
> Filip
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj

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Re: Transformation of rotation

Andre Joost
Am 04.09.2013 16:23, schrieb [hidden email]:
> Hello,
>
> use 7 parameter datum shift - that include rotational parameters for each axis
>
> in proj.4 you use towgs84 statement to define any datum shift.
>

These shift parameters are applied to the axis at the center of the
earth, and not on the surface where we normally use plane projected data
in metres.

Greetings,
André Joost

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Re: Transformation of rotation

support.mn
In reply to this post by phdr_hroch
Hello,

a simple plane rotation theta can be done using the following
formulas for each point:

xx = x*cos(theta) - y*sin(theta);    // xx after, x before
yy = x*sin(theta) + y*cos(tjeta);    // yy after, y before

see also:
http://en.wikipedia.org/wiki/Rotation_(mathematics)#Matrix_algebra

Janne.

--------------------------------------------------------------------------------------

Andre Joost [[hidden email]] kirjoitti:

> Am 04.09.2013 16:23, schrieb [hidden email]:
> > Hello,
> >
> > use 7 parameter datum shift - that include rotational parameters for each axis
> >
> > in proj.4 you use towgs84 statement to define any datum shift.
> >
>
> These shift parameters are applied to the axis at the center of the
> earth, and not on the surface where we normally use plane projected data
> in metres.
>
> Greetings,
> André Joost
>
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj
>

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