[gdal-dev] Precision about scale/offset element in VRT file

[Saâd HESSANE]

Hy all,

The vrt format allow defining the scale and offset element. But the
documentation is not clear about that :

   - *Offset*: This optional element contains the offset that should be
   applied when computing "real" pixel values from scaled pixel values on a
   raster band. The default is 0.0.
   - *Scale*: This optional element contains the scale that should be
   applied when computing "real" pixel values from scaled pixel values on a
   raster band. The default is 1.0.

What that it's mean ? If the value of offset is 1 what that it's change?

And this two elements are use in the *VRTRasterBand* element. What about *
ScaleOffset* and *ScaleRatio* in the *ComplexSource* element?

Thank you.
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