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Then it converts the image into a pseudo-colored image using the color table. This conversion utilizes Floyd-Steinberg dithering (error diffusion) to maximize output image visual quality.</p> <dl> <dt><b>-n</b> <em>colors</em>:</dt> <dd>Select the number of colors in the generated color table. Defaults to 256. Must be between 2 and 256. </dd> <dt><b>-pct</b> <em>palette_file</em>:</dt> <dd>Extract the color table from <em>palette_file</em> instead of computing it. Can be used to have a consistent color table for multiple files. The <em>palette_file</em> must be a raster file in a GDAL supported format with a palette. </dd> <dt><b>-of</b> <em>format</em>:</dt> <dd>Format to generated (defaults to GeoTIFF). Same semantics as the <b>-of</b> flag for gdal_translate. Only output formats supporting pseudocolor tables should be used. </dd> <dt><em>source_file</em>:</dt> <dd>The input RGB file. </dd> <dt><em>dest_file</em>:</dt> <dd>The output pseudo-colored file that will be created. </dd> </dl> <p>NOTE: rgb2pct.py is a Python script, and will only work if GDAL was built with Python support.</p> <h1><a class="anchor" id="rgb2pct_example"></a> EXAMPLE</h1> <p>If it is desired to hand create the palette, likely the simplest text format is the GDAL VRT format. In the following example a VRT was created in a text editor with a small 4 color palette with the RGBA colors 238/238/238/255, 237/237/237/255, 236/236/236/255 and 229/229/229/255.</p> <pre class="fragment">% rgb2pct.py -pct palette.vrt rgb.tif pseudo-colored.tif % more < palette.vrt <VRTDataset rasterXSize="226" rasterYSize="271"> <VRTRasterBand dataType="Byte" band="1"> <ColorInterp>Palette</ColorInterp> <ColorTable> <Entry c1="238" c2="238" c3="238" c4="255"/> <Entry c1="237" c2="237" c3="237" c4="255"/> <Entry c1="236" c2="236" c3="236" c4="255"/> <Entry c1="229" c2="229" c3="229" c4="255"/> </ColorTable> </VRTRasterBand> </VRTDataset> </pre> </div></div><!-- contents --> <!-- start footer part --> <hr class="footer"/><address class="footer"><small> Generated by  <a href="http://www.doxygen.org/index.html"> <img class="footer" src="doxygen.png" alt="doxygen"/> </a> 1.8.5 </small></address> </body> </html>