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

[Saâd HESSANE]

Ok, thank you again Chaitanya,

But what is the function of this two element?


2012/3/23 Chaitanya kumar CH <chaitanya.ch at gmail.com>

> 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.
>>
>> _______________________________________________
>> gdal-dev mailing list
>> gdal-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>>
>
>
>
> --
> Best regards,
> Chaitanya kumar CH.
>
> +91-9494447584
> 17.2416N 80.1426E
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/gdal-dev/attachments/20120323/f7e8e259/attachment-0001.html