How To: Enable transparency for selected features of a feature class
ArcMap does not support different transparency levels on a single feature class or shapefile. Definition query must be performed on a layer to select the desired features before setting the transparency and copying the layer to the data frame. The original layer can then be deleted from the map document without any loss of data from the feature class.
The instructions provided describe how to enable transparency for selected features within a feature class.
In the Table Of Contents, right-click the layer containing the desired features, and click Properties.
In the Layer Properties window, on the Definition Query tab, click Query Builder.
In the Query Builder dialog, build the query expression for the desired attribute, and click OK. For more information on building query expressions, refer to the following documentation, ArcGIS Help: Building a query expression.
Click OK to close the Layer Properties window.
Right-click the layer with the queried features and click Copy.
Right-click the heading of the layers and click Paste Layer(s).
Activate the Effects toolbar by navigating to Customize > Toolbars > Effects.
On the Effects toolbar, ensure that the desired layer is selected in the drop-down, and click the Adjust Transparency button to select the transparency level for the layer.
Note: This layer acts as the transparent layer of data.
To view the transparent features over pre-existing features, use the Table of Contents (display by Drawing Order) and drag the layer containing the transparent features to the top of the list.
To view the current display with other original features, the query expression can be removed from the original feature class, before dragging the layer to the bottom of the list in the Table Of Contents. This is the base layer of data.
<div id='indent' style='padding: 0em,0em,0em,1em;'>i. Right-click the original layer > Properties > Definition Query. ii. Delete the query expression from the Definition Query field, and click OK. iii. Drag the feature class to the bottom of the list of layers in the Table of Contents.