[Mapserver-users] GeoTiff output color problems

[Matthew Perry]

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Hello folks,
 
Testing a new intallation of mapserver here and I'm getting some wierd results when outputting Geotiffs:
 
When I use the following:
 
OUTPUTFORMAT 
  NAME GTiff
  DRIVER "GDAL/GTiff"
  MIMETYPE "image/tiff"
  IMAGEMODE PC256           
  EXTENSION "tif"
END
 
I get this image: http://ktrin.cnrs.humboldt.edu/misc/gtiff_256.tif
 
This has the correct colors but poor quality, plus I would like to have 24 bit output. So I tried the following:
 
OUTPUTFORMAT 
  NAME GTiff
  DRIVER "GDAL/GTiff"
  MIMETYPE "image/tiff"
  IMAGEMODE RGB           
  EXTENSION "tif"
END
 
which gives me this image with bizzare colors (but better resolution): http://ktrin.cnrs.humboldt.edu/misc/gtiff_rgb.tif
 
Both images are properly georeferenced, though. I have tried reversing the order of the bands (in ArcMap 8.3) to no avail. 
 
Any ideas why the Geotiff 24bit color would be innacurate?
 
Thanks for you help,
Matt Perry
Humboldt State University
HostGIS.com
 
 



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Content-Type: text/html; charset=us-ascii

<DIV>Hello folks,</DIV>
<DIV>&nbsp;</DIV>
<DIV>Testing a new intallation of mapserver here and I'm getting some wierd results when outputting Geotiffs:</DIV>
<DIV>&nbsp;</DIV>
<DIV>When I use the following:</DIV>
<DIV>&nbsp;</DIV>
<DIV>
<DIV>OUTPUTFORMAT&nbsp;<BR>&nbsp; NAME GTiff<BR>&nbsp; DRIVER "GDAL/GTiff"<BR>&nbsp; MIMETYPE "image/tiff"<BR>&nbsp; IMAGEMODE PC256&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</DIV>
<DIV>&nbsp; EXTENSION "tif"<BR>END</DIV>
<DIV>&nbsp;</DIV>
<DIV>I get this image: <A href="http://ktrin.cnrs.humboldt.edu/misc/gtiff_256.tif">http://ktrin.cnrs.humboldt.edu/misc/gtiff_256.tif</A></DIV>
<DIV>&nbsp;</DIV>
<DIV>This has the correct colors but poor quality, plus I would like to have 24 bit output. So I tried the following:</DIV>
<DIV>&nbsp;</DIV>
<DIV>
<DIV>OUTPUTFORMAT&nbsp;<BR>&nbsp; NAME GTiff<BR>&nbsp; DRIVER "GDAL/GTiff"<BR>&nbsp; MIMETYPE "image/tiff"<BR>&nbsp; IMAGEMODE&nbsp;RGB&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</DIV>
<DIV>&nbsp; EXTENSION "tif"<BR>END</DIV>
<DIV>&nbsp;</DIV>
<DIV>which gives me this image with bizzare colors (but better resolution): <A href="http://ktrin.cnrs.humboldt.edu/misc/gtiff_rgb.tif">http://ktrin.cnrs.humboldt.edu/misc/gtiff_rgb.tif</A></DIV>
<DIV>&nbsp;</DIV>
<DIV>Both images are properly georeferenced, though. I have tried reversing the order of the bands (in ArcMap 8.3) to no avail. </DIV>
<DIV>&nbsp;</DIV>
<DIV>Any ideas why the Geotiff 24bit color would be innacurate?</DIV>
<DIV>&nbsp;</DIV>
<DIV>Thanks for you help,</DIV>
<DIV>Matt Perry</DIV>
<DIV>Humboldt State University</DIV>
<DIV>HostGIS.com</DIV>
<DIV>&nbsp;</DIV>
<DIV>&nbsp;</DIV></DIV></DIV>
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