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<p class=MsoNormal><font size=2 face=Verdana><span style='font-size:10.0pt;
font-family:Verdana'>Hi all again,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span style='font-size:10.0pt;
font-family:Verdana'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'>Using the GDAL CSharp binding, I am trying to
convert RGB data from a Dataset (MEM driver) to 8 bits gray scaled JPEG.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'>I create a ColorTable of GPI_Gray interpretation type
and populate it with CreateColorRamp with ColorEntries from 0,0,0 to
255,255,255.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'>I set the color interpretation for the new (MEM
driver) dataset single band to GCI_GrayIndex.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'>Then use DitherRGB2PCT and finally CreateCopy with the
JPEG driver.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'>But the output remains empty (1 colour : 0,0,0).<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'>I tried to figure out how gdal_translate may do it
with the –expand gray option but it uses a VRTSourcedRasterBand which
does not seem to be available in CSharp.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'>Thanks,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'>Marc<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Verdana><span lang=EN-GB style='font-size:
10.0pt;font-family:Verdana'><o:p> </o:p></span></font></p>
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