seemingly simple question

[Richard Taylor]

Hello list -

have installed ms4w 4.4.0 and have steadily increased
additions of 'my own' vector and raster layers, getting
the feel of it with primarily only previous experience
with esriworld (but not IMS) and with the Univ Kansas
'flat earth' javascript WMS client.

at this point am blending output from multiple WMS servers
and serving my layers from localhost into the Javascript client
and getting images that are correctly registered in geographic
space however a simple line shapefile from my server
is rendered with a grey background across the entire image
extent. must be in good company, or at least sharing bad
habits with good company in that the 'global_mosaic' layer
from the JPL WMS server also has this grey background where
ever there is no data.

have searched the documentation but unsuccessfully to date
except for transparent png symbols.
What is the best way of setting background of MS output
to transparent, presumably in the mapfile?

thanks in advance

Richard Taylor

my current version of the flat earth WMS javascript client
can be seen at http://www.seascallop.com/COOA_660.html
or any of the larger sizes linked at the bottom of that page