[gdal-dev] GDAL adding overviews adds artifacts to the raster

[Ariel Zerahia]

While trying to add overviews to a raster we observe strange artifacts that
did not exists in the original raster.

here is a link to the original raster:
https://tellurictest.blob.core.windows.net/overviews-artifacts/one.tif?sp=r&st=2018-05-30T08:17:22Z&se=2019-06-08T16:17:22Z&spr=https&sv=2017-11-09&sig=L0WZrO7xYqacRVmXDSPGFLVe6tUYGlnwWh0huaI4%2Fng%3D&sr=b


to generate the overviews I used this:

cp one.tif over_one.tif

gdaladdo -r cubic over_one.tif 2 4 8 16 32 64

here you can see the raster with overviews:
https://tellurictest.blob.core.windows.net/overviews-artifacts/over_one.tif?sp=r&st=2018-05-30T08:20:28Z&se=2019-06-08T16:20:28Z&spr=https&sv=2017-11-09&sig=%2FV2hXg8f0mPLKQyMDODZ3p81Qnkb9GvAF%2B1zgk%2BypKE%3D&sr=b

by looking at both rasters in low zoom levels you can observe the artifacts.

thanks,
Ariel
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