Thanks to Ed McNierney, Frank Warmerdam and Bart van den Eijnden - it seems that ArcMap is requesting a PNG from Mapserver - which then defaults to 256 colours. By changing the OUTPUTFORMAT IMAGEMODE definition for png to RGBA, it has resolved the issue. In the end an easier solution to than I thought it would be. Thanks again guys for the quick response. Regards,
Brendan Power Manager GIS Fire & Emergency Services Authority of WA address: 480 Hay Street Perth WA 6000 postal: Po Box P1174 Perth WA 6844 phone: 9323 9351 mobile: 0417 918 809 fax: 9323 9384 web: www.fesa.wa.gov.au
