[gdal-dev] oblique cuts on a raster using python GDAL

[Javier Jimenez Shaw]

This is producing something nicer, without those "white pixels". It is
adding an alpha band:
gdalwarp 3635_rasters_agreges.jp2 salida.jp2 -cutline
geometry_extraction.shp -crop_to_cutline -cl geometry_extraction -overwrite
-dstalpha

On Mon, 6 Nov 2023 at 14:05, Javier Jimenez Shaw <j1 at jimenezshaw.com> wrote:

> This is working for me (and also in gdal 3.8.0):
>
> gdalwarp 3635_rasters_agreges.jp2 salida.tif -cutline
> geometry_extraction.shp -crop_to_cutline -dstnodata 0 -cl
> geometry_extraction -overwrite -of GTiff
>
> About the "white" pixels inside the image, it could be that a single band
> has a value of 0 (not that strange). Then it is transparent, and you see
> the background color. (to avoid those "color misunderstandings" I have a
> pink background color, that is not white).
>
> On Mon, 6 Nov 2023 at 12:35, Naima Dambrine <naima.etienne at gmail.com>
> wrote:
>
>> Hi Javier,
>>
>> Thank you, good news ...
>>
>> I'm on Ubuntu 20.04 with gdal 3.6.2. Yes, the original raster format is
>> JP2, but my output format is GTiff. Here is exactly what I do :
>>
>> cut_ds = gdal.Warp(outfile, jp2_ds, format='GTiff',
>> cutlineDCName=shape_file_path,
>> cropToCutline=True,
>> copyMetadat=True,
>> dstNodata=0)
>>
>> What I see is that there are still black pixels around the image, as well
>> as white pixels inside the image.
>> Another point to consider is that, despite the use of compression, the
>> output file is 75.3 MB, compared with around 14 MB with a JP2 format. Why
>> is this?
>>
>> my output :
>>
>>
>>
>>
>> Le lun. 6 nov. 2023 à 11:33, Javier Jimenez Shaw <j1 at jimenezshaw.com> a
>> écrit :
>>
>>> Hi Naima
>>>
>>> I have been testing with your dataset. To me, using the GDAL in Ubuntu
>>> 22.04 (3.4.1) seems to be a problem with the JP2 output format. If you
>>> output as geotiff it works fine.
>>>
>>> On Sun, 5 Nov 2023 at 19:43, Rahkonen Jukka via gdal-dev <
>>> gdal-dev at lists.osgeo.org> wrote:
>>>
>>>> Hi,
>>>>
>>>>
>>>>
>>>> Please add gdalinfo of the source image. Even better if you can share
>>>> the image.
>>>>
>>>>
>>>>
>>>> -Jukka Rahkonen-
>>>>
>>>>
>>>>
>>>> *Lähettäjä:* gdal-dev <gdal-dev-bounces at lists.osgeo.org> *Puolesta *Naima
>>>> Dambrine via gdal-dev
>>>> *Lähetetty:* sunnuntai 5. marraskuuta 2023 17.35
>>>> *Vastaanottaja:* gdal-dev at lists.osgeo.org
>>>> *Aihe:* [gdal-dev] oblique cuts on a raster using python GDAL
>>>>
>>>>
>>>>
>>>> Hi ,
>>>>
>>>>
>>>>
>>>> I have problems with oblique cuts on a raster using python GDAL (3.6.2)
>>>>
>>>>
>>>>
>>>> - with this line i obtain black borders around :
>>>>
>>>> gdal.warp('raster-dst' , raster-src',
>>>> cutLineDSName='geometry-extraction.shp', cropToCutline=True)
>>>>
>>>>
>>>>
>>>> - with this one, the crop is not clean on closer inspection: residual
>>>> black pixels around image and white pixels appear in the image.
>>>>
>>>> gdal. warp( 'raster-dst' , raster-src',
>>>> cutLineDSName='geometry-extraction.shp', cropToCutline=True,
>>>> copyMetaData=True, dstNodata=0)
>>>>
>>>>
>>>> I tried, without success, to refine with outputBounds=[minX, maxX,
>>>> minY, maxY], under QGIS directly ….
>>>> I've run out of ideas :/
>>>> A (naive) question comes to mind: Is it possible to make oblique cuts
>>>> with gdal.warp() & co?
>>>>
>>>> Naïma
>>>> _______________________________________________
>>>> gdal-dev mailing list
>>>> gdal-dev at lists.osgeo.org
>>>> https://lists.osgeo.org/mailman/listinfo/gdal-dev
>>>>
>>>
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