Many thanks Sean and Even,

So with rasterio compiled against gdal 3.3 I'll be able to force ignore overviews?
If that deserves a new rasterio unit test I'm happy to send a pull request in the coming days.

Cheers,
Loïc
________________________________________
From: main@rasterio.groups.io <main@rasterio.groups.io> on behalf of Sean Gillies via groups.io <sean=mapbox.com@groups.io>
Sent: 13 November 2020 20:57
To: main@rasterio.groups.io
Subject: Re: [rasterio] Is it possible to ignore existing overview when performing decimated read?

Hi Even,

On Fri, Nov 13, 2020 at 10:38 AM Even Rouault <even.rouault@...<mailto:even.rouault@...>> wrote:
On vendredi 13 novembre 2020 09:05:41 CET Sean Gillies via groups.io<https://urldefense.com/v3/__http://groups.io__;!!DOxrgLBm!U8N393pmVlI170WWlMCwvmrIV7A8JSl9WHWOD7E3re7ET8O3tNpqP7DhM2SV30dTeRRzVSk$> wrote:
> HI Loïc,
>
> I don't think we currently have any option other than to remove the
> overviews. In theory GDAL's OVERVIEW_LEVEL open option could help us, but
> the implementation isn't there. For example, if you used gdalwarp with
> `-ovr NONE` it will set an internal overview level to the value of -1. But
> that bypasses GDALOpenEx (used by rasterio). GDALOpenEx won't let us pass
> `OVERVIEW_LEVEL=-1. It fails with a "Cannot open overview level -1" error.

Was left as an exercice for a contributor:
https://github.com/OSGeo/gdal/pull/3181<https://urldefense.com/v3/__https://github.com/OSGeo/gdal/pull/3181__;!!DOxrgLBm!U8N393pmVlI170WWlMCwvmrIV7A8JSl9WHWOD7E3re7ET8O3tNpqP7DhM2SV30dTK8LUNCg$>

Even

Thanks