I was thinking about this a little bit. There is a way that you could do this, but it may be a little ugly.
If you only want to do this for one (or a few) layer and you don't need to break your data up into too many classes of varied transparency. You could create a layer for each desired classification, have one class in each layer and set an expression in that class to only show the features that you want to assign a particular level of transparency to. You would then set transparency at the layer level. Also, remember that transparency behaves more like a property that would be called opacity. A transparency of 20 is more 'see through' than a transparency of 80. Legends and queries might be a little funky with this arrangement, but you should be able to work around them. David. -----Original Message----- From: Fawcett, David Sent: Fri 9/8/2006 4:44 PM To: 'Hong'; [email protected] Subject: RE: [UMN_MAPSERVER-USERS] Transparency based on classification, possible? No. Transparency is set at the layer level. Take a look at: http://mapserver.gis.umn.edu/docs/reference/mapfile/layer If you want to use URL variable substitution, you could probably change the transparency of the LAYER on the fly, but not at the class level. David. -----Original Message----- From: UMN MapServer Users List [mailto:[EMAIL PROTECTED] On Behalf Of Hong Sent: Friday, September 08, 2006 4:37 PM To: [email protected] Subject: [UMN_MAPSERVER-USERS] Transparency based on classification, possible? Hello, Is it possible to set the transparency of layer symbolization based on the classification? Something similar to the effect of: LAYER ... CLASS EXPRESSION "expr0" TRANSPARENCY 50 END CLASS CLASS EXPRESSION "expr1" TRANSPARENCY 70 END CLASS END LAYER Thanks.
