[mapserver-users] Can't remove artifacts aroung polygons with Mapserver 6.0.3

[Ei Fujioka]

Hello,

I've upgraded Mapserver from 5.2 to 6.0.3 and struggling in removing 
artifacts that appear around polygons. I didn't see this problem with 5.2.

See the screen shots of the same tile with 5.2 and 6.0 followed by 
OUTPUTFORMAT definition.

5.2
http://seamap-dev.env.duke.edu/cache/images/mapserver_52_gd_png_rgba.png

   OUTPUTFORMAT
     NAME "PNG"
     MIMETYPE "image/png"
     DRIVER "GD/PNG"
     EXTENSION "png"
     IMAGEMODE "RGBA"
     TRANSPARENT TRUE
   END


6.0
http://seamap-dev.env.duke.edu/cache/images/mapserver_6_agg_png_rgba.png

   OUTPUTFORMAT
     NAME "PNG"
     MIMETYPE "image/png"
     DRIVER "AGG/PNG"
     EXTENSION "png"
     IMAGEMODE RGBA
     TRANSPARENT TRUE
     FORMATOPTION "GAMMA=0.7"
   END # OUTPUTFORMAT


You can see whitish lines around the small squares in 6.0.
I changed GAMMA=xxx (e.g. 1.0, 0.5, 0.0) but it doesn't seem to have any 
effects on the image.
When I set IMAGEMODE to PC256, the artifacts disappear but I need it to 
be transparent. The document 
(http://mapserver.org/mapfile/outputformat.html) mentions that PC256 is 
only supported by GD/GIF and GD/PNG but it seems working with AGG/PNG.


Could someone give me advice how to remove the artifacts?
Do I simply need to upgrade to 6.4?
(I didn't as it's not available from RPM)


Here is the output of mapserv -v.

MapServer version 6.0.3 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG SUPPORTS=PROJ 
SUPPORTS=AGG SUPPORTS=CAIRO SUPPORTS=FREETYPE SUPPORTS=ICONV 
SUPPORTS=FRIBIDI SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT 
SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT SUPPORTS=WCS_SERVER 
SUPPORTS=SOS_SERVER SUPPORTS=FASTCGI SUPPORTS=THREADS SUPPORTS=GEOS 
INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE


Thanks,

-- 
========================
   Ei Fujioka
   Research Scientist
   Nicholas School
   Duke University

   (919) 613-8021 Ext. 2
   efujioka at duke.edu
========================