Suzie Larrivée

Modeling Geospatial Databases with Plug-Ins for Visual Languages: A Pragmatic Approach and the Impacts of 16 Years of Research and Experimentations on Perceptory

Modeling geospatial databases for GIS applications has always posed several challenges for system analysts, developers and their clients. Numerous improvements to modeling formalisms have been proposed by the research community over the last 15 years, most remaining within academia. This paper presents generic extensions (called Plug-Ins for Visual Languages or PVL) to facilitate spatial and temporal modeling of databases. For the first time, we explain its intrinsic relationship with an extended repository and how it has been influenced by pragmatic lessons learned from real life projects. We describe how we use PVLs with UML and how 16 years of fundamental research, diverse experimentations and feedbacks from users over the world shaped our approach. The final section presents Perceptory, a free repository-based UML+ PVL CASE developed to improve geospatial database modeling.

Fondement de la modélisation conceptuelle des bases de données géospatiales 3D

For the last 15 years, designing 2D databases has benefited from new or extended formalisms proposed by the GIS research community. However, three-dimensional representations have been significantly more frequent in the recent years, especially in 3D computer graphics and in 3D GIS. In spite of this fact, there exist a lot of confusion in fundamental notions and there has been insofar no proposal for solutions aimed at facilitating the conceptual modeling of 3D geospatial databases as required for GIS applications. The first difficulty met when someone wants to design a database model for 3D applications may seem bizarre but is in fact very fundamental: the very definitions of « 3 » and of « D » ! This paper proposes fundamental notions and a solution to create conceptual models of geospatial databases for 3D applications: theoretical concepts, 3D extensions for UML, integration with Perceptory spatial and spatio-temporal PVL, simple and complex cases. MOTS CLES: definitions 3D, SIG 3D, base de donnees geospatiales, modelisation conceptuelle, UML 3D, PVL 3D, Perceptory.

How to enrich the semantics of geospatial databases by properly expressing 3d objects in a conceptual model

Geospatial conceptual data models represent semantic information about the real world that will be implemented in a spatial database. When linked to a repository, they offer a rich basis for formal ontologies. Several spatial extensions [5, 15, 17] have been proposed to data models and repositories in order to enrich the semantics of spatial objects, typically by specifying the geometry of objects in the schema and sometimes by adding geometric details in the repository. Considering the success of such 2D spatial extensions as well as the increased demand for 3D objects management, we defined a 3D spatial extension based on the concept of PVL already used in Perceptory and elsewhere. This paper presents 3D concepts and 3D PVL to help defining the geometry of 3D objects in conceptual data models and repositories. Their originality stems from the fact that no similar solution exists yet for real-life projects. The enrichment of the meaning of 3D objects geometries is discussed as well as its impact on costs, delays and acquisition specifications.