[OSGeo-Discuss] WCS/WMS accuracy tests?

[Frank Warmerdam]

Steven M. Ottens wrote:
> On Dec 9, 2009, at 3:44 PM, Frank Warmerdam wrote:
> 
>> Steven M. Ottens wrote:
>>> Mapserver doesn’t offset the data unless it is physically impossible
>>> (non-native, non-multiple resolutions, extents which don’t snap to source
>>> data) but produces a multi-band geotiff where the source data is single
>>> band.
>> Steven,
>>
>> Thanks for the excellent post.  I'd be interested in following up on the
>> singleband / multiband issue with MapServer WCS when you have time.  I
>> vaguely recall there being an issue with this at one point but I thought it
>> was solved quite a while ago.  So if it persists in 5.6.0 I'd love a chance
>> to fix it.
> 
> I'm happy to help, the map file and source data can be found here: http://dl.dropbox.com/u/175548/data.zip and the server itself is accessible through http://research.geodan.nl/cgi-bin/mapserver56/mapserv.exe?map=maps/corine.map&
> 
> If you need anything else let me know.

Steven,

I believe you would want to change this:

OUTPUTFORMAT
   NAME GTiff
   DRIVER "GDAL/GTiff"
   MIMETYPE "image/tiff"
   IMAGEMODE RGB
   EXTENSION "tif"
END

to:


OUTPUTFORMAT
   NAME GTiff
   DRIVER "GDAL/GTiff"
   MIMETYPE "image/tiff"
   IMAGEMODE BYTE
   EXTENSION "tif"
END

IMAGEMODE RGB essentially tells MapServer to produce a normal 24bit RGB
image result using the normal painting mechanisms.  Using IMAGEMODE BYTE
tells mapserver to produce a BYTE raster result and incidentally will
match the number of bands to the source image.   BYTE (and INT16 and FLOAT)
are often more appropriate for WCS when you want to preserve original
pixel values exactly rather than visually.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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