[gdal-dev] Re: Scale dependent VRT for overviews

[Even Rouault]

Jukka,

I think you could achieve what you want by adding a <Overview> element (see 
http://www.gdal.org/gdal_vrttut.html ) inside the <VRTRasterBand> element. The 
dataset pointed by the <SourceFilename> in <Overview> can be a .vrt.

So, schematically, you would have something like 100_percent.vrt :

<VRTDataset>
   <VRTRasterBand>
       <Overview>
           <SourceFilename relativeToVRT="1">50_percent.vrt</SourceFilename>
           <SourceBand>1</SourceBand>
       </Overview>
   </VRTRasterBand>
</VRTDataset>

and in 50_percent.vrt :

<VRTDataset>
   <VRTRasterBand>
       <Overview>
           <SourceFilename relativeToVRT="1">25_percent.vrt</SourceFilename>
           <SourceBand>1</SourceBand>
       </Overview>
   </VRTRasterBand>
</VRTDataset>

and so on

> 
> -Jukka Rahkonen-
> 
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