[gdal-dev] 4 point, projective warping

[Manuel Massing]

Hi Jeffrey,

> I've thought about implementing a projective transform in the qgis
> georeferencer, so if you're interested I'll let you know when I get around
> to it.

If this interest you, I have just commited an initial implementation of
projective warping (see https://trac.osgeo.org/qgis/changeset/13987)
to the qgis georeferencer, which is based on the gdalwarper.

In principle, it should be relatively easy to integrate this transform into a 
custom version of gdalwarp. 

Maybe there's even interest to have such a transform in GDAL proper? 
I would be willing to contribute the code to GDAL, although the model
fitting step uses a singular value decomposition, so this would require
some dependency on  a linear algebra package (I wouldn't consider it wise to
reimplement numerical algorithms from scratch, with their numerous caveats).

cheers,

	Manuel