[gdal-dev] Does the VRT SimpleSource element's OVERVIEW_LEVEL open option apply to the Overview element?

[Even Rouault]

Hi Sean,

> 
> Does the OVERVIEW_LEVEL open option described in
> https://www.gdal.org/gdal_vrttut.html#gdal_vrttut_format apply to VRT
> Overview elements? 

No. Not implemented in code, doc, or in the .xsd schema at
https://github.com/OSGeo/gdal/blob/master/gdal/data/gdalvrt.xsd ;-)

> If not, could it be made to work
> or does that go against the grain of VRT features?

I believe this could be implemented reasonably easily.


A (not pretty) workaround to avoid proliferation of VRT files is to use a 
inline nested VRT. That is, in the <SourceFilename> element of <Overview>, you 
can put a VRT definition as a CDATA construct.

<SourceFilename>![CDATA[<VRTDataset>...</VRTDataset>]]></SourceFilename>


Actually, an easier alternative for the precise use case you expose would be 
to do:
ln -s cog_ovrs.tif cog_novr.tif.ovr

Even

-- 
Spatialys - Geospatial professional services
http://www.spatialys.com