What is Federated Information System (FIS)

Currently there are many domain areas in Computer Science interested in the integration of various information sources. Federated Databases, Semantic Web, and Automated Web Services are some of them. Particularly in the geographic information area, newer and better technologies and devices are being created in order to capture a large amount of information about Earth. All of this geographic information is analyzed and stored at various levels of detail in Geographic Information Systems (GISs), possibly distributed on the Web. Then a fast search for geographic information on the Web will return several links representing parts of our world. But what happens when someone needs information that is divided into more than one system? For example, information about rivers in a country can be obtained by querying two or more systems. Although distribution of information is one of the main problems, there are some others; these systems have been developed by various entities with different points of view and vocabularies, and here is when face heterogeneity problems arise. They are encountered in every communication between interoperating systems where interoperability refers to interaction between information from various sources involving the task of data integration to combine data.