[gdal-dev] Creating Geotiff is slow

[Even Rouault]

> I am puzzled by this behavior... Is there something wrong with my GDAL
> settings ?
> Is there a way to speed up the GeoTIFF creation ? Why is it faster using
> python ?

There might be several factors:

- if with rasterio you read completely the image into memory, and then write it, parallel 
decompression is perhaps more effective. gdal_translate (actually the mechanics behind it) 
tries to use smaller read & write windows by default. You could try to set the 
GDAL_SWATH_SIZE configuration option to 250000000 so that the full band is read at once.

- but I suspect the reason might be due to the Sentinel2 band reporting 15 bits, and 
gdal_translate instructing the GTiff driver to use that setting, whereas I'm not sure if rasterio 
does the same by default. Writing 15 bits / pixel isn't a super fast code path in the GeoTIFF 
driver. You could try adding -co NBITS=16

Even


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