Abstract: A geographic information system for operation with an accreditation database storing identities of information providers and indications of whether each of those information providers is a member of an accreditation group, the system comprising a geographic information database for storing a list of information sources external to the database together with, for each source, the identity of an information provider associated with the source and one or more geographic definitions associated with the source, a search unit for receiving from a user an indication of a geographic location, accessing the geographic information database to form a set of information sources whose geographic definitions encompass that location and associated with an information provider that is indicated by the accreditation database as being a member of one or more predetermined accreditation groups, and making that set of information sources available to the user.

Abstract: An object oriented data processing system configured to store objects and to store definitions of relationships between the objects, and to process the objects in accordance with the defined relationships, the system being configured so as to support definitions of relationships of two types; a first type of relationship whereby objects can be related such that one object in a hierarchy related to another object by a relationship of the first type is deemed to belong to a set defined by the other object; and a second type of relationship distinct from the first type of relationship and whereby objects can be hierarchically related such that a child object related to a parent object by a relationship of the second type is deemed to inherit characteristics of the parent object and, to an extent specified in the relationship of the second type, a proportion of a characteristic of a further object related to the said parent object by a relationship of the first type.