opacity slider for individual layers within one map service

RhysDonoghue

I'm doing something that I would have thought should be quite simple.  I have a table of contents with checkboxes to turn layers on and off.  All of the layers are coming from only one dynamic map service.  I am making the layers visible/invisible by using an ArrayCollection like this:

<esri:Map>
     <esri:ArcGISDynamicMapServiceLayer id="dynamicCensusBlockPoints"
         url="http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Demographics/ESRI_Census_USA/MapServer">
         <esri:visibleLayers>
             <mx:ArrayCollection>
                 <mx:Number>0</mx:Number> <!-- Show census block points only -->
             </mx:ArrayCollection>
         </esri:visibleLayers>
     </esri:ArcGISDynamicMapServiceLayer>
</esri:Map>

(from http://resources.esri.com/help/9.3/arcgisserver/apis/flex/apiref/com/esri/ags/layers/ArcGISDynamicMapServiceLayer.html
)

I am populating the ArrayCollection via ActionScript.  Everything is working properly, however now I want to add in an opacity slider for each layer.  Obviously it is easy enough to change the layer opacity for the whole map service but I want to do it for individual layers.  I can create the opacity sliders against each layer easy enough but I can't figure out how to get the opacity property in the ArrayCollection.  Worst case scenario, I have two options 1: tell the client they cannot have opacity sliders on the layers, or 2: I repeat the dynamic map service 12 times for each of my 12 layers, set the visible layers for each of the map services to only one for each map service, and apply the opacity to each map service.  Surely it can be done easier than this though.  Anyone have any ideas?

RobertScheitlin__GISP

Rhys,

  Don't waste any more of your time on this as currently setting the opacity of individual layer in a map service is NOT possible. To understand why you have to understand how ArcGIS Server handles requests from the client. Currently the request is made and the request can specify which layers are to be turned on or off but the map service does not have any method to expose the opacity of an individual layer, the request is processed and an image is returned (i.e. a JPG or PNG, etc not individual layers that can be adjusted). In ArcGIS Server 10.1 you are suppose to be able to have more control of the returned data (i.e. you can change the symbology of a feature before it is returned).