Filling Out the Context Area Classes
The <Context_Area>, the parent class of the <Observation_Area> found in observational products, contains a set of classes that may be used as appropriate to provide high-level, searchable description of the associated product.
In fact, the only difference between the content of the Context_Area and the Observation_Area is that all the subclasses in the Context_Area are optional, whereas in the Observation_Area the <Time_Coordinates>, <Investigation_Area>, <Observing_System>, and <Target_Identification> classes are required.
For detailed description of the classes and attributes in the Context_Area, see Filling Out the Observation Area Classes.
For additional explanation, see the PDS Standards Reference, or contact your PDS node consultant.