Using Ontologies for Integrity Constraint Definition

摘要

To assure the quality of acquired data quite a number of quality checks have to be carried out before the data is inserted into the database. For these checks quality requirements and integrity rules defined by the application play an important role (for example constraints between object classes). To-date there is no standardized formalism for the definition of constraints or rules within the existing data model. In particular for mobile data acquisition such formalization technique would be of great benefit, since it could support an automatic or semiautomatic process of quality consistency checking already during the acquisition workflow. Standard interfaces like OGCs (Open Geospatial Consortium) WFS (Web Feature Service) allow for an access and also for an update of heterogeneous databases through the Internet (transactional mode of WFS)[Plan et al. 2004]. But the important aspect of providing information about rules and/or constraints is unfortunately not supported by the WFS- interface, because there are no possibilities to encode integrity constraints within the feature class description of the WFS provided. In this paper ontologies as a description of integrity constraints in a formal way are discussed. It is described how such constraints can be defined in SWRL (Semantic Web Rule Language), which is a combination of OWL (Web Ontology Language) and RuleML (Rule Markup Language). It is shown how these rules can be used as an extension to the data schema information, available for example through the WFS interface. This research work is being carried out as part of a bundle research project called "Advancement of Geoservices" (contract number: F.Nr. 03F0381A) funded by the German Ministry of Education and Research (BMBF- Bundesministerium fuer Bildung und Forschung) and German Research Foundation (DFG-Deutsche Forschungsgemeinschaft). The project aims at the conception and the prototype implementation of a sophisticated open standards based mobile geodata acquisition system. The project consortium comprises University of Osnabmeck (Research Centre for Geoinformation and Remote Sensing), University of Karlsruhe (Institute for Photogrammetry and Remote Sensing), EML (European Media Laboratory) Heidelberg and University of the Bundeswehr Munich (AGIS GIS Lab).