[gdal-dev] Apply filter on VRT

Saâd HESSANE saad.hessane at gmail.com
Thu Apr 12 09:51:25 EDT 2012


Thank you Chaitanya for the answer,

I do the test with the kenel element like the documentation :


> <Kernel normalized="1">
>     <Size>3</Size>
>     <Coefs>0.11111111 0.11111111 0.11111111 0.11111111 0.11111111
> 0.11111111 0.11111111 0.11111111 0.11111111</Coefs>
> </Kernel>
>
It's the same probleme, gdal_translate crash. But if the VRTRasterBand have
just one KernelFilteredSource element, gdal_translate work fine and apply
the filtre correctely.

The poblem appears if there are more than one KernelFilteredSource element
in the VRTRasterBand.



2012/4/12 Chaitanya kumar CH <chaitanya.ch at gmail.com>

> Saâd,
>
> There should be a Kernel element in a KernelFilteredSource.
> FYI, all the pixels whose kernel has a nodata pixel will be reported as a
> nodata pixel.
>
>  On Wed, Apr 11, 2012 at 3:20 PM, Saâd HESSANE <saad.hessane at gmail.com>wrote:
>
>>  Hy all,
>>
>> I have a VRT file generated with buildvrt utility :
>>
>> <VRTDataset rasterXSize="52436" rasterYSize="32400">
>>>   <SRS>...</SRS>
>>>   <GeoTransform>...</GeoTransform>
>>>   <VRTRasterBand dataType="UInt16" band="1">
>>>     <NoDataValue>0</NoDataValue>
>>>     <ColorInterp>Gray</ColorInterp>
>>>     <ComplexSource>
>>>       <SourceFilename relativeToVRT="1">1.tif</SourceFilename>
>>>       <SourceBand>1</SourceBand>
>>>       <SourceProperties RasterXSize="8449" RasterYSize="6429"
>>> DataType="UInt16" BlockXSize="8449" BlockYSize="1" />
>>>       <SrcRect xOff="0" yOff="0" xSize="8449" ySize="6429" />
>>>       <DstRect xOff="0" yOff="0" xSize="10721" ySize="8158" />
>>>       <NODATA>0</NODATA>
>>>     </ComplexSource>
>>>     <ComplexSource>
>>>       <SourceFilename relativeToVRT="1">2.tif</SourceFilename>
>>>       <SourceBand>1</SourceBand>
>>>       <SourceProperties RasterXSize="8772" RasterYSize="6407"
>>> DataType="UInt16" BlockXSize="8772" BlockYSize="1" />
>>>       <SrcRect xOff="0" yOff="0" xSize="8772" ySize="6407" />
>>>       <DstRect xOff="43664" yOff="25993" xSize="8772" ySize="6407" />
>>>       <NODATA>0</NODATA>
>>>     </ComplexSource>
>>>   </VRTRasterBand>
>>> </VRTDataset>
>>>
>>
>> It's work fine with a gdal_translate.
>> Now I want to apply a filter kernel to the VRT. I have to use the
>> KernelFilteredSource.
>> The gdal api say that VRTKernelFilteredSource is a sub-class of
>> VRTComplexSource. So a VRTKernelFilteredSource *is *a VRTComplexSource.
>> But if I replace VRTComplexSource by VRTKernelFilteredSource,
>> gdal_translate crash. This is the new VRT :
>>
>> <VRTDataset rasterXSize="52436" rasterYSize="32400">
>>>   <SRS>...</SRS>
>>>   <GeoTransform>...</GeoTransform>
>>>   <VRTRasterBand dataType="UInt16" band="1">
>>>     <NoDataValue>0</NoDataValue>
>>>     <ColorInterp>Gray</ColorInterp>
>>>     <KernelFilteredSource>
>>>       <SourceFilename relativeToVRT="1">1.tif</SourceFilename>
>>>       <SourceBand>1</SourceBand>
>>>       <SourceProperties RasterXSize="8449" RasterYSize="6429"
>>> DataType="UInt16" BlockXSize="8449" BlockYSize="1" />
>>>       <SrcRect xOff="0" yOff="0" xSize="8449" ySize="6429" />
>>>       <DstRect xOff="0" yOff="0" xSize="10721" ySize="8158" />
>>>       <NODATA>0</NODATA>
>>>     </KernelFilteredSource>
>>>     <KernelFilteredSource>
>>>       <SourceFilename relativeToVRT="1">2.tif</SourceFilename>
>>>       <SourceBand>1</SourceBand>
>>>       <SourceProperties RasterXSize="8772" RasterYSize="6407"
>>> DataType="UInt16" BlockXSize="8772" BlockYSize="1" />
>>>       <SrcRect xOff="0" yOff="0" xSize="8772" ySize="6407" />
>>>       <DstRect xOff="43664" yOff="25993" xSize="8772" ySize="6407" />
>>>       <NODATA>0</NODATA>
>>>     </KernelFilteredSource>
>>>   </VRTRasterBand>
>>> </VRTDataset>
>>>
>>
>> It's weird, I expected a polymorphism between VRTComplexSource and
>> VRTKernelFilteredSource.
>> So the question : how can I apply a filter to a VRT?
>> 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
>
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