GI-cat: a mediation solution for building a clearinghouse catalog service

The development of a clearinghouse catalog solution arises from the need of interoperability among different communities. Such a component provides search and access capabilities across catalogs, inventory lists and their registered resources. In an SOA (Service Oriented Architecture) approach, a clearinghouse catalog solution may be implemented as a Broker/Mediation component applying mediation services to address standards multiplicity. An example of such solution is GI-cat. In this work we describe its architecture. GI-cat implements a distributed approach in order to achieve scalability and accuracy. It implements metadata querying and browsing in an asynchronous way. As far as query distribution is concerned, it provides advanced features such as the possibility to retrieve intermediate query results and related feedbacks. The main GI-cat components, their interfaces and roles are described and discussed. A specific geobrowser was developed in order to demonstrate the advanced GI-cat functionalities: GI-go. GI-cat was successfully used in international initiatives and programmes such as GEOSS and EC-funded projects.