[Qgis-user] Transform vectordata using affine transformation

[Bo Victor Thomsen]

Hi list -

One of my customers just received a data file, where the coordinates is 
not in any projection: Center of map data is (0,0), units in mm. not 
meter, maybe some rotation too. However, at least it's a planar 
coordinate system (I hope).

Instead of sending the #¤%&! data file back to the "GIS no-good" 
architect who send it , I've decided to - once and for all - to find a 
method to  transform this kind of data to a reasonable CRS using an 
affine transformation.

  * I'm aware of the Processing algorithm "Affine transform" that can do
    the actual transformation once I know the translation, rotation and
    scale coefficients of the transformation.
  * And I know how to find the affine transformation matrix using a set
    of points from the data that corresponds with a set of points in the
    destination CRS.

However, Is there any plug-in that can:

 1. Digitize a set of positions from the original data.
 2. Digitize or manually set the corresponding positions in the
    destination CRS
 3. Create the translation, scale and rotation parameters using data
    from (2)
 4. Run the "Affine transformation" algorithm to transform the data to
    the right position in the chosen CRS

In short - a Georeferencer for vector data

  * A name of a functioning plug-in would be lovely

  * A set QGIS classes/methods that could help with establishing the
    transformation matrix and other stuff would be really nice

  * A "No" to all my wishes would suck. However, In that case, I can
    start developing without have the nagging feeling that someone has
    done this before

-- 
Med venlig hilsen / Kind regards

Bo Victor Thomsen

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