[Qgis-developer] Re: vector affine transformation

[Jack R]

On Friday 27 November 2009 04:23:31 pm Agustin Lobo wrote:
I am just updating GUI of Gereoreferencer but I could try to implement 
georeferencing for vectors.

> The problem with "Capture From Map Canvas" is
> that you need 2 canvas, unless both the original and the reference
> objects are
> be very close. The Georeferencer plugin opens the raster to be
> processed in a special window, but that window does not
> let you display a vector. Perhaps that would be enough, a window
> such as the one in Georeferencer but for vectors.
> 
> By now, I'm going to try using Coordinate capture twice, once for the
> vector to be warped and the other for the reference object. Then
> input both sets of coordinates into R and calculate
> the affine transformation matrix there. Then I can either
> go on with the actual transformation in R (package spatstat)
> and then export to QGIS (this is comfortably done thanks to
> manageR) or use your plugin.
> 
> Agus
> 
> Maurício de Paulo wrote:
> > Hum... you mean like georreferencing the vectors?
> > While reading your mail I thought about a "Capture From Map Canvas" for
> > the two translation coordinates.
> > Well, I don't know how the georreferencer is written, but I can try to
> > think about reusing it's code. I'm going to take a look at it.
> > Thanks for the tip.
> > Best regards,
> > Mauricio de Paulo
> >
> > On Fri, Nov 27, 2009 at 9:36 AM, Agustin Lobo <aloboaleu at gmail.com
> > <mailto:aloboaleu at gmail.com>> wrote:
> >
> >     Hi!
> >
> >     It's often the case in which you actually don't know
> >     the values for the affine transformation for
> >     plugin qgsAffine but just some pairs of corresponding coordinates.
> >     I understand that including a facility such as the one for raster
> >     georeference would be very useful but quite a work, thus I wonder
> >     if the raster georeference plugin could actually output this
> >     information which could then be fed to qgsAffine?
> >
> >     Agus
> 
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-- 
С уважением,
Рысь