[gdal-dev] VRT band datatype issue

[Even Rouault]

On lundi 27 août 2018 09:17:32 CEST GUIMMARA, Sébastien (External) [FR] wrote:
> Hi all,
> 
> I am creating a VRT that translate from a 16bit dataset to a 8bit. Here is
> the raster band :
> 
> <VRTRasterBand dataType="Byte" band="1">
>       <ComplexSource>
>       ...
>       <Exponent>0.75</Exponent>
>       <SrcMin>0</SrcMin>
>       <SrcMax>65535</SrcMax>
>       <DstMin>0</DstMin>
>       <DstMax>255</DstMax>
>       <SourceProperties DataType="UInt16"/>
>       </ComplexSource>
> </VRTRasterBand>
> 
> However, gdal_info 2.2 tells me that this VRT has DataType=Byte (OK), but
> the min/max are still 0/65535 instead of 0/255.
> 
> How is it possible ?

An inappropriate optimization that didn't take into account exponential 
scaling.
Fixed per
https://github.com/OSGeo/gdal/commit/c2b188a49baef70e4e05614be14caaa520341302

Even

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