[gdal-dev] Reading a VRT file & overview usage

[Even Rouault]

Angus,

> But the second command ignores the overviews and downloads the full
> resolution imagery leading to very long download times. Is it expected
> behaviour that all re-sampling methods except 'nearest neighbour' need to
> request the full resolution data? Can't they apply the selected re-sampling
> method to the overviews? Is it something to do with the way I created my
> VRT file?

I can't confirm with the following little test

gdal_translate byte.tif test.tif -outsize 2048 2048
gdal_translate test.tif left.tif -srcwin 0 0 1024 2048 -b 1 -b 1 -b 1
gdal_translate test.tif right.tif -srcwin 1024 0 1024 2048  -b 1 -b 1 -b 1
gdalbuildvrt vrt.vrt left.tif right.tif
gdaladdo left.tif
gdaladdo right.tif
python -c "from osgeo import gdal; ds = gdal.Open('left.tif', gdal.GA_Update); 
ds.GetRasterBand(1).GetOverview(2).Fill(0)"

copy left.tif, right.tif and vrt.vrt on S3

gdal_translate /vsis3/mybucket/vrt.vrt out.tif -r bilinear -outsize 128 128

Works fine with GDAL 2.4.4 and master

If you can come up with a minimum reproducing scenario (input files + script/
command to reproduce), please file a ticket on github

Even

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