ucar.visad.display.
DisplayMaster class is a wrapper
around a visad.DisplayImpl and manages a list of
Displayable objects. The
ucar.unidata.view.geoloc.MapProjectionDisplay is
the most commonly used DisplayMaster in the IDV.
Displayable class provides support 
for encapsulating one or more displayed data objects together 
with their display-dependent state.
DisplayableData class holds a
visad.DataReference, a set of visad.ScalarMap-s
and a visad.DataRenderer that control the depiction of 
the Data in the display.Displayable subclasses used in the IDV include: