Ontology based description of satellite imageries for application ...

The problem for this situation is that the data repository must understand the matching between dataand applications (user tasks), only then it can respond to a certain query in a proper way. Theaforementioned issues are caused by missing relationships between data domain and applicationdomain, and lacking of descriptions how entities of the data domain can be linked to certain tasks ofthe application domain.3. Related worksIn recent years, many researchers [Barb 2008, Campedel 2009, Ruan 2006, Shao 2008, Silva 2004,Tomai 2008] devote to extend image retrieval methodologies from low-level characteristics tosemantic content and relationship. They focus on describing the content of satellite imagery and theunderlying processing chains in order to retrieve information of satellite images. An adaptedontology is applied in order to describe the real world objects with human knowledge for extractingthem from satellite imageries. Ontology based approach is applied in this paper to describe satelliteimageries regarding to specific applications, for which satellite imageries can be of use, instead ofdescribing information inside the datasets itself.In [Kiemle 2002], they present a model describing earth observation data within a digital library. Themodel defines generic earth observation product classes and their relationships. Primary data aregrouped into product classes, which are described by common features like creation time, and spatiotemporalcoverage. The approach can facilitate user search for data and can be extended by definingnew definitions like product types, product component types and product parameters. It is difficult tomanage the system by mapping primary data to product groups if primary data belongs to more oneproduct group.A further work [Podwyszynski 2009] presents an approach, on that satellite imageries are describedbased on properties of sensor and the related applications. The system is divided into two domains,the application domain and data domain; the application domain describes theapplication/phenomenon users are working with. The data domain describes the properties ofsatellite imageries. The two domains are related with each other through a measurement component.Users are able to search data based on applications they are interest in without any knowledge of lowlevel data characteristics. However, the system only describes properties of each image such asspatial resolution, processing level instead of describing the properties of sensors. It will be timeconsuming and errors prone for data providers especially when data is updated or reorganized and itis also difficult to extend when new sensors are built.4. MethodThe ontology-based approach is applied to describe satellite sensors and user requirement incircumstances of earth observation and the relationship between them. The concept of ontology canbe expressed as an encoding of a specific domain in order to share knowledge and understandingCopyright 2011 Shaker Verlag Aachen, ISBN: 978-3-8440-0451-9