University of Twente Student Theses


A unified data model for spatial data access

Tsadik, Banchialem Melke (2011) A unified data model for spatial data access.

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Abstract:Data kept in various organizations sow different levels of heterogeneity due to fragmentation. Various segments in the organizations experience different data heterogeneity such as syntactic heterogeneity, schematic heterogeneity and semantic heterogeneity. This research deals with schematic heterogeneity so that the data sources are categorized into three groups such as structured data , semi-structured data and unstructured data based on the characteristics of their schemas. The research particularly deals with the schematic heterogeneity of structured and semi-structured data so as to facilitate data integration. Spatial Data Infrastructures has a purpose in facilitating spatial data use and sharing, and can be an effective platform to aid in data integration. This research aim at providing an interface that allows a unified way to access and use disparate data sources available at various SDI nodes. Schema mapping and transformation techniques are used to overcome schematic heterogeneity and as a means of facilitating heterogeneous spatial data integration. The schema mapping process is done at the schema level and the schema transformation process is done at the data level. In schema mapping process the the mapping rules from source to target schema are specified based upon the query expression posed on the target schema. This specification is done by using OML(Ontology Mapping Language). The actual data transformation process is based on the mapping rules and undertaken in two steps such as data extraction from the required data sources, execution of transformation functions on the extracted data to transform the data into the target. The result of this research can be used as one functionality within an SDI framework for effective data integration. The result also aim to assist users to follow the same procedure or methodology used for resolving schematic heterogeneity of their data sources and get integrated information for their spatial applications. Keywords spatial data heterogeneity,structured data,semi-structured data,Spatial Data Infrastructure,spatial data integration, schema mapping, schema transformation
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Programme:Geoinformation Science and Earth Observation MSc (75014)
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