On Sun, 26 Sept 2021 at 02:49, Bo Victor Thomsen <bo.victor.thom...@gmail.com> wrote: > > 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 #ยค%&! 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: > > Digitize a set of positions from the original data. > Digitize or manually set the corresponding positions in the destination CRS > Create the translation, scale and rotation parameters using data from (2) > Run the "Affine transformation" algorithm to transform the data to the right > position in the chosen CRS > > In short - a Georeferencer for vector data
The good news is that this is close...ish. A lot of the groundwork API has been done, and there's an open PR at https://github.com/qgis/QGIS/pull/41386 which adds vector support to the georeferencer. This PR needs some work though, so I'm hoping someone steps up and funds a couple of days development so that I can clean it up and get it merged... Nyall > > 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 > > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user