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

[Chaitanya kumar CH]

Saâd,

A VRT raster band can be derived from more than one source.

Offset and Scale elements apply to the whole VRT raster band.
The ScaleOffset and ScaleRatio perform the same task but it is done only on
that particular ComplexSource.

On Fri, Mar 23, 2012 at 3:43 PM, Saâd HESSANE <saad.hessane at gmail.com>wrote:

> 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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-- 
Best regards,
Chaitanya kumar CH.

+91-9494447584
17.2416N 80.1426E
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