[mapserver-users] set COLOR to transparent?

[Wendell Turner]

Is there a way to turn a pixel transparent?  That is,
something like:

 CLASS
  EXPRESSION ([red] > 200 AND [green] > 200 AND [blue] > 200 )
  TRANSPARENT
 END

Or is there a way to set the pixel to the index of the
transparent entry in the color table?

Also, is there an 'ELSE' clause to the class/expression
statements?  That is, if the expression fails, leave other
pixels alone.  Using a class and an expression seems to
reset all other pixels.

Thanks,

Wendell