Thanks for posting this! I had to no idea that this functionality existed. Is this documented somewhere?
On Thu, Oct 27, 2011 at 4:58 AM, Chaitanya kumar CH <chaitanya...@gmail.com>wrote: > J, > > A vrt file[1] can implement your requirements. It can create a 'lookup > table' to translate your pixel values. > Start by running gdalbuildvrt on your raster file and modify it to contain > the LUT element. It will look something like this: > > <VRTDataset rasterXSize="512" rasterYSize="512"> > <VRTRasterBand dataType="Byte" band="1"> > > <ComplexSource> > <SourceFilename relativeToVRT="1">utm.tif</SourceFilename> > <SourceBand>1</SourceBand> > <ScaleOffset>0</ScaleOffset> > > <ScaleRatio>1</ScaleRatio> > <LUT>0:0,253:253,254:255</LUT> > <SrcRect xOff="0" yOff="0" xSize="512" ySize="512"/> > > <DstRect xOff="0" yOff="0" xSize="512" ySize="512"/> > > </ComplexSource> > </VRTRasterBand> > <VRTRasterBand dataType="Byte" band="2"> > <ComplexSource> > > <SourceFilename relativeToVRT="1">utm.tif</SourceFilename> > <SourceBand>2</SourceBand> > <ScaleOffset>0</ScaleOffset> > > <ScaleRatio>1</ScaleRatio> > <LUT>0:0,253:253,254:255</LUT> > <SrcRect xOff="0" yOff="0" xSize="512" ySize="512"/> > > <DstRect xOff="0" yOff="0" xSize="512" ySize="512"/> > > </ComplexSource> > </VRTRasterBand> > <VRTRasterBand dataType="Byte" band="3"> > <ComplexSource> > > <SourceFilename relativeToVRT="1">utm.tif</SourceFilename> > <SourceBand>3</SourceBand> > <ScaleOffset>0</ScaleOffset> > > <ScaleRatio>1</ScaleRatio> > <LUT>0:0,253:253,254:255</LUT> > <SrcRect xOff="0" yOff="0" xSize="512" ySize="512"/> > > <DstRect xOff="0" yOff="0" xSize="512" ySize="512"/> > > </ComplexSource> > </VRTRasterBand> > </VRTDataset> > > > The LUT element is the key here. It tells the VRT driver to keep the values > from 0 to 253 as they are and change 254 to 255. > Remember to replace the appropriate parts. > > [1]: http://www.gdal.org/gdal_vrttut.html > > On Thu, Oct 27, 2011 at 12:40 PM, joolek <joole...@gmail.com> wrote: > >> Yes, this is exactly what I am struggling to do. Gdal is so powerful - but >> I can't get it working. >> J >> >> >> On 26 Oct 2011, at 17:10, "Chaitanya kumar CH [via OSGeo.org]"<[hidden >> email] <http://user/SendEmail.jtp?type=node&node=6935299&i=0>> wrote: >> >> Do you want to convert just the pixels with the values (254,254,254)? >> >> On Wed, Oct 26, 2011 at 9:33 PM, joolek <[hidden >> email]<http://user/SendEmail.jtp?type=node&node=6933215&i=0> >> > wrote: >> >>> Hi I basically want to convert all the 254 254 254 into 255 255 255... is >>> this possible? >>> >>> -- >>> View this message in context: >>> http://osgeo-org.1803224.n2.nabble.com/254-into-255-tp6931988p6933182.html >>> Sent from the GDAL - Dev mailing list archive at Nabble.com. >>> _______________________________________________ >>> gdal-dev mailing list >>> [hidden email] <http://user/SendEmail.jtp?type=node&node=6933215&i=1> >>> http://lists.osgeo.org/mailman/listinfo/gdal-dev >>> >> >> >> >> -- >> Best regards, >> Chaitanya kumar CH. >> >> +91-9494447584 >> 17.2416N 80.1426E >> >> _______________________________________________ >> gdal-dev mailing list >> [hidden email] <http://user/SendEmail.jtp?type=node&node=6933215&i=2> >> http://lists.osgeo.org/mailman/listinfo/gdal-dev >> >> ------------------------------ >> If you reply to this email, your message will be added to the discussion >> below: >> http://osgeo-org.1803224.n2.nabble.com/254-into-255-tp6931988p6933215.html >> To unsubscribe from 254 into 255, click here. >> >> >> ------------------------------ >> View this message in context: Re: 254 into >> 255<http://osgeo-org.1803224.n2.nabble.com/254-into-255-tp6931988p6935299.html> >> >> Sent from the GDAL - Dev mailing list >> archive<http://osgeo-org.1803224.n2.nabble.com/GDAL-Dev-f2022644.html>at >> Nabble.com. >> >> _______________________________________________ >> gdal-dev mailing list >> gdal-dev@lists.osgeo.org >> http://lists.osgeo.org/mailman/listinfo/gdal-dev >> > > > > -- > Best regards, > Chaitanya kumar CH. > > +91-9494447584 > 17.2416N 80.1426E > > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev >
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