Modeling Spatial Data in the MADS Conceptual Model

Despite the well-established benefits of conceptual modeling for application design, current spatio-temporal conceptual models do not cope satisfactorily with designers' requirements. In this paper we first identify the goals of a spatio-temporal conceptual model and then we describe the MADS model along its structural and spatial dimensions. As the modeling concepts are orthogonal, the proposed model achieves both simplicity (as concepts are independent from each other) and expressive power (as concepts may be freely associated). The model, which includes the features of the ODMG standard model for object-oriented systems, has been implemented by translating it into operational models of existing products. Experience gained by modeling a number of applications enabled us to assess the advantages of MADS with respect to traditional entity-relationship modeling. A visual schema editor and a visual query editor are being develope

MADS: un modèle conceptuel pour des applicationsspatio-temporelles

Malgré les bienfaits reconnus de l'approche conceptuelle pour la modélisation d'applications, les modèles conceptuels spatio-temporels existants ne satisfont pas les besoins des concepteurs. Dans cet article nous identifions d'abord les objectifs d'un modèle conceptuel spatio-temporel et ensuite nous présentons le modèle MADS selon trois axes: concepts structu-rels, concepts spatiaux, concepts temporels. L'orthogonalité des concepts permet d'obtenir un modèle à la fois simple (puisque ces concepts sont indépendants) et puissant (puisque les con-cepts peuvent être combinés librement). Le modèle a été implanté et des traductions existent vers d'autres modèles opérationnels. L'article décrit brièvement les réalisations en cours ou prévues pour offrir aux utilisateurs une interface conceptuelle de définition et d'accès aux bases de données spatio-temporelles. Nous donnons également les résultats d'une expérience de mo-délisation qui a permis de vérifier les qualités du modèle

Généralisation automatique des objets linéaires: le cas des routes

Plazanet Corinne. Généralisation automatique des objets linéaires: le cas des routes. In: Mappemonde, 1998/1. p. 8

Measurement, Characterization And Classification For Automated Line Feature Generalization

This paper proposes to describe geometrical characteristics of linear features by segmenting lines and qualifying sections detected according to different criteria at several levels ("hierarchical" process). Such a kind of line representation should provide basic and complementary information in order to guide global and local decisions. The ultimate aim is to choose and sequence adequate generalization tools and parameter values. KEYWORDS: Automated linear feature generalization, segmentation, characteristic point detection, measurement, clustering INTRODUCTION Generalization is often described as an holistic process, due to the large number of constraints and interactions that must be taken into account. This paper addresses issues related to linear feature intrinsic generalization. At first, the main issue for such a generalization is that every linear feature seems to be a particular case (at least for a significant level of generalization). This may come out from the fact that a ..