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Qualitative topological relationships for objects with possibly vague shapes: implications on the specification of topological integrity constraints in transactional spatial databases and in spatial data warehouses

Abstract : In spatial databases currently implemented, natural phenomena are usually represented by geometries with well-defined boundaries. Such a description ignores the reality that characterizes the wave form of some spatial objects (floodplains, lakes, forest stands, etc.).. The quality of the recorded data is degraded because of the discrepancy between the réalitée and description. This thesis addresses this problem by proposing a new approach to represent spatial objects with vague shapes and characterize their topological relationships. The proposed model, called QMM model (acronym for Qualitative Min-Max model) uses the concepts of minimum and maximum extensions to represent the uncertain part of an object. A set of adverbs can express the vague shape of an object (eg a broad area with a Partially boundary), and the uncertainty of topological relations between two objects (eg weakly Contains Contains fairly, etc.. ). This approach is coarser than other competing approaches (modeling by fuzzy sets or probabilistic modeling). But it requires a complex process of data acquisition. Moreover it is relatively easy to implement with existing systems management databases. This approach is then used to control the quality of data in spatial databases and data warehouses specifying spatial integrity constraints based on the concepts of model QMM. An extension of the constraint language OCL (Object Constraint Language) has been designed to specify topological constraints involving objects with vague shapes. Existing software (OCLtoSQL tool developed at the University of Dresden) has been extended to allow the automatic code generation of SQL constraint when the database is managed by a relational system. An experiment of this tool was conducted with a database used for the management of agricultural spraying. For this application, the approach and the tool appeared very efficient. This thesis also includes a study of the integration of heterogeneous spatial databases where objects are represented with the QMM model. New results were produced and application examples were explained.
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Submitted on : Monday, August 27, 2012 - 3:01:33 PM
Last modification on : Friday, October 23, 2020 - 4:49:24 PM
Long-term archiving on: : Wednesday, November 28, 2012 - 3:32:05 AM

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  • HAL Id : tel-00725614, version 1

Citation

Lofti Bejaoui. Qualitative topological relationships for objects with possibly vague shapes: implications on the specification of topological integrity constraints in transactional spatial databases and in spatial data warehouses. Géographie. Université Blaise Pascal - Clermont-Ferrand II; Université Laval, Québec (Canada), 2009. Français. ⟨NNT : 2009CLF21924⟩. ⟨tel-00725614⟩

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