Page 1 of 3 Next  S.K. Ghosh School of Information Technology Indian Institute of Technology, Kharagpur skg@sit.iitkgp.ernet.in  Manoj Paul School of Information Technology Indian Institute of Technology, Kharagpur mpaul@sit.iitkgp.ernet.in Abstract: Heterogeneity in GIS makes the data produced in one context, unusable in another context. The heterogeneity arises both at the syntactic and semantic level. With the increasing demand of GIS among large scale of users, interoperable sharing of GIS has become important. The root of the heterogeneities has been identified and possible solution has been found out in this paper. Service based computing has been proposed to be next generation approach for GIS sharing and interoperability. In this context, standards of OGC have been discussed. The use of ontology for conceptual modeling of the domain can resolve the semantic heterogeneity also. All these issues taken together can bring interoperable sharing of GIS information across organization boundaries. 1. Introduction The exchange of information has become a crucial factor in today’s economy. Many activities in business world involve different organizations that have to work together, and use existing information whenever possible, in order to reach a common goal. Interoperability requires to be ensured for seamless exchange of information among diverse information source. Interoperable information system consists of geographically distributed systems having different data models and processing capabilities. Present trend of ensuring interoperability among heterogeneous systems deals with ensuring uniform access of information among these systems. Similar situation has also been faced in GIS and their applications. 1.1 GIS Interoperability Popularity of GIS in government and municipality institutions induces an increasing amount of available geospatial information. The primary collector of GIS data like city services, local offices, local telecom, public utilities, water and power supply services, etc collects spatial data of different context, where most of data in databases are georeferenced. Information that exists in different spatial databases may be useful for many other GIS applications. But, information communities find it difficult to locate and retrieve data from other sources, in reliable and acceptable form. The major hindrance in GIS interoperability in such systems is because of obscure semantics, diversity of data sets, and the heterogeneity of existing systems in terms of data modelling concepts, data encoding techniques and storage structures [1]. The realization of interoperable systems is weighty process, as a consequence of two main system characteristic – distributed data sources and their heterogeneity. Current efforts to integrate geographic information embrace the idea of meta-data standards as the key to information sharing and analysis. These include the Federal Geographic Data Committee (FGDC) and the National Spatial Data Infrastructure (NSDI), GeoSpatial One-Stop, and the U.S. Geological Survey’s The National Map as well as standards from the International Standards Organization (ISO) for geospatial meta-data. The NSDI attempts to bring together geographical information sources from all levels of government and other organizations into a single point of entry for easier access to data. 1.2 Social Issues There are other issues behind successful integration of GIS. Organizations are collecting data individually and not willing to share their own information in public without commitment. In that case, centralized control is not applicable and not practical, since the ownership of data is in domain of organizations that they belong, and no one wants to share his own information with public. An approach is necessary for distributed integration of GIS sources with the authority of the databases left to its owner. To achieve interoperability among these distributed GIS sources, the first prerequisite is that individuals and organizations know each other and the data they possess. Second, there must be a willingness to make data available to users outside the source organization. Given that an organization is open to interoperability, it must announce its existence and willingness to exchange information. Then other individuals can discover the organization and assess whether there may be interest in accessing information. Thus a mechanism is required to be developed, where others can access GIS information as services [7, 8]. If services provided from the GIS can be integrated, interoperability can be ensured among the GIS community. GIS data can be provided as services where each individual GIS provider can share their data, update and upgrade data repositories independently. The semantics of GIS services should be captured in the form of ontology for ensuring semantic coherence among GIS providers.
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