[gdal-dev] Re: 254 into 255
Hermann Peifer
peifer at gmx.eu
Fri Oct 28 13:58:25 EDT 2011
On 27/10/2011 10:58, Chaitanya kumar CH wrote:
>
> A vrt file can implement your requirements. It can create a 'lookup
> table' to translate your pixel values...
Chaitanya,
I just tried to translate an Int32 GeoTIFF with pixel values 111..523
into a byte-type GeoTIFF with values 1..44, using the LUT as indicated
below.
I noted that in the resulting GeoTIFF, the previous NODATA areas have
now a pixel value of 1. Is this expected behaviour or rather some sort
of "over-extrapolation" of my lookup table (as I would assume) ?
Thanks in advance, Hermann
<VRTDataset rasterXSize="8786" rasterYSize="6443">
...
<VRTRasterBand dataType="Int32" band="1">
<NoDataValue>0.00000000000000E+00</NoDataValue>
<ColorInterp>Gray</ColorInterp>
<ComplexSource>
<SourceFilename relativeToVRT="1">ch00_form.tif</SourceFilename>
<SourceBand>1</SourceBand>
<SourceProperties RasterXSize="8786" RasterYSize="6443"
DataType="Int32" BlockXSize="256" BlockYSize="256" />
<SrcRect xOff="0" yOff="0" xSize="8786" ySize="6443" />
<DstRect xOff="0" yOff="0" xSize="8786" ySize="6443" />
<LUT>111:1,112:2,121:3,122:4,123:5,124:6,131:7,132:8,...</LUT>
</ComplexSource>
</VRTRasterBand>
</VRTDataset>
More information about the gdal-dev
mailing list