[mapserver-users] Using IMAGECOLOR to create a transparency mask

[Gregor at HostGIS]

> Perhaps I'm not clear on what constitutes "8-bit pseudocolored map 
> generation". I am using the AGG/PNG driver with TRANSPARENT ON.

FWIW, here is my favorite IMAGETYPE block for generating AGG PNGs with 
transparency:

   OUTPUTFORMAT
     NAME "png"
     MIMETYPE "image/png"
     DRIVER "AGG/PNG"
     EXTENSION "png"
     IMAGEMODE RGBA
     TRANSPARENT OFF
   END

It does set transparent off, but the RGBA uses alpha blending to make 
transparency anyway. We love it.

-- 
Gregor Mosheh / Greg Allensworth    BS, A+, Network+, Security+, Server+
System Administrator, Lead Programmer
HostGIS development & hosting services, http://www.HostGIS.com/

"Remember that no one cares if you can back up,
  only if you can restore." - AMANDA