The user may define subclasses of this class.
The update operation consists of four parts.
operation: the type or choice of update operation.
linkName: the name of an attribute used as a unique identifier. This implies that the geographic object carrying the update information belongs to a subclass of
GeographicObject, (or another subclass below GeographicObject), and that the subclass has an attribute used to uniquely identify the object in the addressee's (receiver's) database. The value for linkName is the name of that attribute. It is the user's responsibility to ensure that the values for the attribute ensure uniqueness.
effective: the date and time when the new data will or has taken effect can be stated.
remarks: comments may be added.