[Qgis-developer] Re: vector affine transformation

[Jack R]

Hello,
I am just updating Georeferencer GUI but I could try to implement 
georeferencing for vectors.

> Forgot to mention that a panel in which the parameters
> could be entered both as you have them and ordered as the
> affine transformation matrix would be appreciated by
> most users. I think this is how ArcView has it (I do not
> use it myself). I find this document useful:
> www.quantdec.com/GIS/affine.htm
> Agus
> Agustin Lobo wrote:
> > 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
> > > -- Dr. Agustin Lobo
> > > Institut de Ciencies de la Terra "Jaume Almera" (CSIC)
> > > LLuis Sole Sabaris s/n
> > > 08028 Barcelona
> > > Spain
> > > Tel. 34 934095410
> > > Fax. 34 934110012
> > > email: Agustin.Lobo at ija.csic.es <mailto:Agustin.Lobo at ija.csic.es>
> > > http://www.ija.csic.es/gt/obster
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--
С уважением,
Рысь