public abstract class ALcdViewshedObserver extends Object
Abstract class that represents a viewshed observer.
Most ILcdViewshed instances are created with respect to
an observer. The observer can be positional (TLcdPositionalViewshedObserver)
or directional (TLcdDirectionalViewshedObserver).
This class is opaque, and its concrete implementations should be thought of as part of an enumeration.
TLcdDirectionalViewshedObserver,
TLcdPositionalViewshedObserver