Doc: RasterIO(): document how overviews are selected

[rouault]

No description provided.

[coveralls]

coverage: 67.686% (-0.003%) from 67.689% when pulling 0adb0c5 on rouault:doc_rasterio_overview into 78d5980 on OSGeo:master.

[mdsumner]

just here to say this could also mention the warper app lib? (and the cog driver specifically, as opposed to the tile server drivers ... I think)

I will put this on my todo but wanted to ask about it 🙏

[rouault]

just here to say this could also mention the warper app lib? (and the cog driver specifically, as opposed to the tile server drivers ... I think)

the warp lib has a slightly different logic (I guess it could be aligned to work with the arbitrary 1.2 ratio of RasterIO() if consistency was needed). Cf lines 2732-2755 of gdalwarp_lib.cpp if you want to document it.
The COG driver is a different beast, and its doc already explains how overviews are handled

[mdsumner]

just here to say this could also mention the warper app lib? (and the cog driver specifically, as opposed to the tile server drivers ... I think)

the warp lib has a slightly different logic (I guess it could be aligned to work with the arbitrary 1.2 ratio of RasterIO() if consistency was needed). Cf lines 2732-2755 of gdalwarp_lib.cpp if you want to document it. The COG driver is a different beast, and its doc already explains how overviews are handled

ah, excellent thank you that's helpful