[gdal-dev] How to specify 'OUTPUT' when warping (reproject)

[ky]

Hi,
I don't really know what you are trying to do with a vector layer as input
for gdal.Warp as it is used more like a cutline to clip a raster rather as
an input, as gdal.Warp expects a raster input/output but
to make it work you must pass options as keyword argument, not as
positional argument, like bellow:

warp = gdal.Warp('/home/ubuntu/pepe.tif', my_input_vector_layer,
options=options)

Hope it helps!



On Fri, Oct 3, 2025 at 1:01 PM AF via gdal-dev <gdal-dev at lists.osgeo.org>
wrote:

> Hello,
> A PyQGIS code needs to reproject one raster layer from a CRS to a new
> one. To begin with, I've tried to use only the minimal required options
> so the snippet reads:
>              parameters = {
>                  'INPUT': my_input_vector_layer,
>                  'SOURCE_CRS': QgsCoordinateReferenceSystem(source_PROJ),
>                  'TARGET_CRS': QgsCoordinateReferenceSystem(target_PROJ),
>                  'RESAMPLING': 1,
>                  'DATA_TYPE': 4,
>                  'OUTPUT': '/home/ubuntu/my_new_raster.tif'
>                  }
>              terrain = processing.run('gdal:warpreproject', parameters)
> However, this doesn't do much as terrain is simply a dictionary with the
> keyword 'OUTPUT' and my_new_raster.tif is never created. Obviously I
> must be doing something wrong and suspect that might be related to
> 'OUTPUT'. The documentation at
>
> https://docs.qgis.org/testing/en/docs/user_manual/processing/toolbox.html#output-parameter-widget
> didn't dissipate my doubts so I'm unsure how to proceed.
> I also tried (an alternative method) calling gdal.Warp directly (not
> sure if this method is preferable to using processing.run) but it keeps
> saying that it only takes 2 arguments. I found a few examples online but
> they all have more than 2 arguments. For example
>              options = gdal.WarpOptions(dstSRS=target_PROJ)
>              warp = gdal.Warp('/home/ubuntu/pepe.tif',
> my_input_vector_layer, options)
>              warp = None
> complains about including 3 and not 2 arguments. Same if I try including
> all arguments at warp.
> Thanks.
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