Hi Oliver, Are you using mapserver's OFFSITE parameter, and/or do your tiff files have a nodata pixel set ? What happens if you convert your tiff to 32bit RGBA? (Not suggesting this is a valid workaround, just trying to narrow down the reasons for this).
-- thomas On 18 April 2013 15:27, Oliver Christen <oliver.chris...@camptocamp.com>wrote: > dear all > > Im having some issue when applying PROCESSING "RESAMPLE=AVERAGE" or > "RESAMPLE=BILINEAR" on some geotiff with transparency. > Either a clear or dark artifact appears on the border of the image, as > seen on these examples: > > http://dev.camptocamp.com/**files/mapserver/fuzzy_edge_**AVERAGE.png<http://dev.camptocamp.com/files/mapserver/fuzzy_edge_AVERAGE.png> > http://dev.camptocamp.com/**files/mapserver/fuzzy_edge_**BILINEAR.png<http://dev.camptocamp.com/files/mapserver/fuzzy_edge_BILINEAR.png> > > if I specify no PROCESSING at all, the transparency is correct (but not > the image "quality" which I wanted to improve with the PROCESSING ): > http://dev.camptocamp.com/**files/mapserver/fuzzy_edge_**NOPROCESSING.png<http://dev.camptocamp.com/files/mapserver/fuzzy_edge_NOPROCESSING.png> > > at first I though the problem may have been caused by a fuzzy edge on the > transparent edges in the geotiff: > http://dev.camptocamp.com/**files/mapserver/fuzzy_edge.png<http://dev.camptocamp.com/files/mapserver/fuzzy_edge.png> > so I retreated one image to have clean edges: > http://dev.camptocamp.com/**files/mapserver/clean_edge.png<http://dev.camptocamp.com/files/mapserver/clean_edge.png> > > but I couldnt see much difference in the result: > http://dev.camptocamp.com/**files/mapserver/clean_edge_**AVERAGE.png<http://dev.camptocamp.com/files/mapserver/clean_edge_AVERAGE.png> > http://dev.camptocamp.com/**files/mapserver/clean_edge_**BILINEAR.png<http://dev.camptocamp.com/files/mapserver/clean_edge_BILINEAR.png> > > there is no visible artifact for all border multipe of 90° (horizontal and > vertical edges), only the non 90° edges show that problem. > > Im not knowledgeable with image manipulation and resampling with > transaprency, so I dont know if this is normal or not. > > Any idea if there is some way to "solve" this "problem" ? > > thank you for your attention > > best regards > Oliver > > > > -- > Camptocamp SA > Oliver Christen > PSE A > CH-1015 Lausanne > > www.camptocamp.com > > +41 21 619 10 23 (direct) > +41 21 619 10 10 (centrale) > +41 21 619 10 00 (fax) > > ______________________________**_________________ > mapserver-users mailing list > mapserver-users@lists.osgeo.**org <mapserver-users@lists.osgeo.org> > http://lists.osgeo.org/**mailman/listinfo/mapserver-**users<http://lists.osgeo.org/mailman/listinfo/mapserver-users> >
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