[Gdal-dev] Do we need to specifically set band's min, max on writting?

[Frank Warmerdam]

Joaquim Luis wrote:
> Hi,
> 
> When saving a dataset to a file do we have to specifically say what are 
> datasets min and max?
> And if yes, how do we do that? I searched but didn't find any 
> "GDALSetRasterMinimum"
> I am using GDALRasterIO( hBand, GF_Write, ...) and thought band min, max 
> were being
> set automatically but a gdalinfo -stats shows this (the rest, as far as 
> I can see, is ok)
> ....
> Band 1 Block=1781x1 Type=Float32, ColorInterp=Gray
>  Minimum=-1.#IO, Maximum=-1.#IO, Mean=-1.#IO, StdDev=-1.#IO
>  Metadata:
>    STATISTICS_MINIMUM=-1.#IND
>    STATISTICS_MAXIMUM=-1.#IND
>    STATISTICS_MEAN=-1.#IND
>    STATISTICS_STDDEV=-1.#IND

Joaquim,

You do not need to set raster min/max values yourself.  They are normally
computed on request.  The above likely means you have some pixels - perhaps
unwritten portions - which have invalid floating point values.  This
messes up the min/max calculations for floating point.

Best regards,
-- 
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