GDAL Python Bindings – Using GDAL Translate/Addo

gdalpython

I'm trying to update a python script using gdal, moving from a subprocess to the actual python bindings but finding the documentation a bit lacking.

My original sub process –

cmd = f"RASTER_PROJ=$(gdalsrsinfo -o wkt_esri --single-line {source_raster}) &&" \
      f"gdal_translate -of {gdal_output} -co COMPRESS=LERC -co QUALITY=75 -co BLOCKSIZE=512 -a_srs \"$RASTER_PROJ\" {source_raster} {destination_raster} && " \
      f"gdaladdo -r average --config COMPRESS_OVERVIEW LERC {destination_raster} 2"
subprocess.call(cmd, shell=True)

My python excerpt –

#translate
translate_options = gdal.TranslateOptions(gdal.ParseCommandLine(f"-of {gdal_output} -co COMPRESS={compression} -co QUALITY=75 -co BLOCKSIZE=512"))
gdal.Translate(destination_raster, source_raster, options=translate_options)

#addo
image = gdal.Open(destination_raster, 1)
gdal.SetConfigOption('COMPRESS_OVERVIEW LERC', 'DEFLATE')
image.BuildOverviews('AVERAGE', [2], gdal.TermProgress_nocb)
del image

This works but ideally I would be creating the overviews the same way as the translate or alternatively setting the image variable first and inputting into the translate function, however I haven't been able to do either without errors.

I've found no documentation on the bindings for BuildOverviews or Addo so am just cobbling things together from SE currently. Is there a better way?

Best Answer

There is no Pythonized version of the gdaladdo utility. From the source code of gdaladdo https://github.com/OSGeo/gdal/blob/master/apps/gdaladdo.cpp it can be seen that the code mainly reads the config options and executes GDALBuildOverviews.

if( nLevelCount > 0 &&
GDALBuildOverviews(hDataset,pszResampling, nLevelCount, anLevels,
                   nBandCount, panBandList, pfnProgress,
                   nullptr) != CE_None)

{

BuildOverviews is documented in the GDAL Python API documentation within gdal.Dataset https://gdal.org/python/osgeo.gdal.Dataset-class.html as https://gdal.org/python/osgeo.gdal.Dataset-class.html#BuildOverviews

Some Python examples can be found from the GDAL autotests. The best test to look is probably the one that is testing the GeoTIFF overviews https://github.com/OSGeo/gdal/blob/master/autotest/gcore/tiff_ovr.py.

For me it seems that you are doing the things right. One option to avoid the separate buildOverviews step could be to use the COG driver https://gdal.org/drivers/raster/cog.html instead of GeoTIFF because COG generates the overviews by the same.

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