[mapserver-users] nodata transparencies

Travis Kirstine traviskirstine at gmail.com
Mon Oct 24 16:08:45 EDT 2011


Hi All

I have a raster layer of 8 bit RGB orthophoto with the source data as
GeoTiff tiles (tile index) .  Some of the source images have the
nodata (0,0,0) defined in the metadata some do not.  Can MS
automatically determine the nodata and use that as a transparency for
each image in the tile index?

The issue that I am having is that I have a large coverage area that
is composed of  RGB tiled uncompressed geotiffs with real nodata
values at the edges of the coverage and tiles on the interior of the
coverage are RGB tiled compressed ycbcr geotiffs with no nodata
defined.   If I use the OFFSITE 0,0,0 parameter in my mapfile the
resultant images will have holes on the interior of the image ().

I have tried scaling the images however it appears that JPEG
compressed YCBCR images do not scale well

Regards


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