Adam Nielsen via QGIS-User <[email protected]> writes:

>>   Transform Failed: Could not create destination file.
>
> I ran QGIS from the console and got an additional error message:
>
>   ERROR 1: Attempt to create -2147483648x-2147483648 dataset is illegal,
>   sizes must be larger than zero.
>
> The problem seems to be something to do with the CRS - QGIS isn't just
> mapping a pixel in the raster image to a point on the map, it also
> needs the source image to have a valid CRS for some reason.
>
> I set the CRS to EPSG:3857 (which wasn't enough on its own), then
> reprojected it to my project's CRS, and then tried to georeference the
> reprojected file and this worked.
>
> I'm not quite sure why it failed with the original CRS, or having no
> CRS at all but I must confess I really don't understand the way a CRS
> interacts with QGIS.
>
> For the time being it looks like reprojecting everything to a different
> CRS before georeferencing will serve as a usable workaround.

There is
  project CRS (display, default for new layers)
  layer CRS

My view of how it should be, and my experience, is that the input file
to the georeferencer generally does not have a CRS.  A recent example
for me is a "plot plan", or map from a survey (a legal document from a
Real Surveyor, from the Registry of Deeds).  This instance is a pdf with
no geo information, a scan from a paper map that was filed in 1930.  It
has no CRS at all.  It is unlikely the surveyor tied to the then-in-use
datum -- definitely not noted on the plan.

In georeferencing, I had a project with CRS of UTM zone 19 in 6319 (my
national datum), and clicked plot plan points and points from the
existing qgis project (property lines from the govt, and my measurements
of boundary monuments), and then I got a tiff which has a CRS tag
matching that project CRS.   That has been my experience uniformly with
georeferencing, but I have done with this LTRs up to 3.44, and have not
tried 4.0 georeferencing.

Please explain what you did to get this to work, and when it failed,
much more precisely.  I can't parse "set the CRS to", and "reprojected
it to".

I'm guessing there is a bug that your case is triggering and that you
are avoiding it, and that it would be better (for qgis overall
long-term) to find and fix it.
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