[gdal-dev] using gdal.Warp to reproject a GTiff with an external nodata mask (.msk)

[Even Rouault]

Le 27/01/2025 à 17:04, Even Rouault via gdal-dev a écrit :
>
> Maxime,
>
>
> you need to do in 2 steps, with something like (didn't test, slight 
> modifications may be needed):
>
> - slightly modify your first step, to reproject to an intermediate 
> RGBA dataset, with dstAlpha=yes. That temporary dataset may be a VRT, 
> or a GeoTIFF with a lossless compression (ie DEFLATE)
>
> - convert from RGBA to RGB+mask with gdal.Translate(out, 
> tmp_dataset_of_previous_step, bandList=[1,2,3], maskBand=4, 
> creationOptions=["COMPRESS=JPEG", "PHOTOMETRIC=YCBCR", "TILED=YES", 
> "BIGTIFF=YES"])
>
>
if you want an external mask to be generated you also need to run the 
gdal.Translate() step under


with gdal.config_option("GDAL_TIFF_INTERNAL_MASK", "NO"):


> Even
>
>
> Le 27/01/2025 à 16:58, Maxime Demers via gdal-dev a écrit :
>> Hi everybody, I hope you are all well!
>>
>> I have an issue that I would need help about if possible.
>> I would like to use the GDAL Python bindings to reproject a TIFF that 
>> has an external nodata mask stored in a separate |.msk| file. Also, 
>> this is important to me to keep the jpeg compression.
>> After some tests, I found out that |gdal.Warp| does not reproject the 
>> |.msk|
>> Is there  a way to acheive what I am trying to do?
>> |import os from osgeo import gdal IN_RASTER = os.path.join(r"C:\\", 
>> "data", "Ortho", "Ortho2024_32187_10cm_mask.tif") OUT_RASTER = 
>> os.path.join(r"C:\\", "data", "Ortho", 
>> "Ortho2024_3857_10cm_mask.tif") src = gdal.Open(IN_RASTER) dst = 
>> gdal.Warp(    OUT_RASTER,    src,    format="GTiff",   
>>  dstSRS="EPSG:3857",    creationOptions=["COMPRESS=JPEG", 
>> "PHOTOMETRIC=YCBCR", "TILED=YES", "BIGTIFF=YES"],   
>>  callback=gdal.TermProgress_nocb ) dst = None|
>>
>>
>>
>> 	
>>
>> **
>>
>> *Maxime Demers*
>>
>> Analyste en géomatique
>>
>> Service de la planification
>>
>> et de la gestion du territoire
>>
>> Tél. : 819 823-8000 poste 2360
>>
>>
>> _______________________________________________
>> gdal-dev mailing list
>> gdal-dev at lists.osgeo.org
>> https://lists.osgeo.org/mailman/listinfo/gdal-dev
> -- 
> http://www.spatialys.com
> My software is free, but my time generally not.
> "De l'égo à l'égoût, il n'y a qu'une bouche mal refermée", André Isaac
>
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-- 
http://www.spatialys.com
My software is free, but my time generally not.
"De l'égo à l'égoût, il n'y a qu'une bouche mal refermée", André Isaac
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