Semantic and conceptual issues in geographic information systems

SCOPUS: ed.jinfo:eu-repo/semantics/publishedSpecial feature on Semantic and Conceptual Issues in GIS (SeCoGIS

Conceptual Modeling for Federated Geographical Information Systems over the Web

A conceptual model provides the best support for federating heterogeneous datastores into a unified framework and elaborating a global consistent description of all available data. It therefore plays a central role for exchange of information within the coming information society. This paper introduces a conceptual model for applications using spatio-temporal data. We discuss in particular the features which support spatial and temporal modeling. An example of conceptual design is given using a pedology application. Advantages of our approach for database design are assessed through comparison with traditional geographical information systems modeling techniques

Spatio-Temporal Conceptual Models: Data Structures + Space + Time

Nowadays, many applications need data modeling facilities for the description of complex objects with spatial and/or temporal facilities. Responses to such requirements may be found in Geographic Information Systems (GIS), in some DBMS, or in the research literature. However, most of existing models cover only partly the requirements (they address either spatial or temporal modeling), and most are at the logical level, hence not well suited for database design. This paper proposes a spatio-temporal modeling approach at the conceptual level, called MADS. The proposal stems from the identification of the criteria to be met for a conceptual model. It is advocated that orthogonality is the key issue for achieving a powerful and intuitive conceptual model. Thus, the proposal focuses on highlighting similarities in the modeling of space and time, which enhance readability and understandability of the model

MurMur: Database Management of MultipleRepresentations

Successful information management implies the ability to design accurate representations of the real world of interest to targeted applications. Current systems do not provide representation schemes supporting the diversity of user needs. In the context of interoperability, as in Web access to heterogeneous data sources, they can-not properly integrate the diversity of stored representations. The objective of the European project described inthis paper, MurMur 1 , is to enhance GIS (or DBMS) functionality so that, relying on more flexible representation schemes, users may easily manage information using multiple representations. The added functionality will support multiple coexisting representations of the same real-word phenomena (semantic flexibility), including representations of geographic data at multiple resolutions (cartographic flexibility). This will in particular make possible a semantically meaningful management of multiscale, integrated, and temporal geo-databases

Modeling Time from a Conceptual Perspective

Although many temporal models have been proposed in the literature, there is still need for a conceptual model capturing the essential semantics of time-varying information that is free of implementation concerns. This paper first discusses important criteria to be considered when assessing the ÒconceptualÓ quality of a temporal model. Then, it presents the main temporal features of MADS, a spatio-temporal conceptual model. The focus is on identifying issues that are either open or controversial, and discussing alternatives, if any. Finally, it is shown how the model may be implemented on top of either TSQL2 or a traditional, non-temporal data model

MurMur: A Research Agenda on MultipleRepresentations

One of the most publicized goals of modern computer society is to provide flexible access to information for everybody, anywhere, anytime. To make data management systems successful in satisfying user quest for information, an abstractolute requirement is the capability of tailoring the information to the peculiar needs of the targeted user. Unfortunately, this is a domain where current technology fails to support adequate functionality. Basically, existing approaches to such versatility rely on the idea that all possible views of a piece of information can be derived from a single ultimate representation. This may work in a centralized setting, but it is definitely unlikely to provide a sufficient framework in distributed, interoperable environments. This paper presents a research and development project that intends to explore the issue related to representation and management of multiple representations of the same reality. A specific focus of the project is spatio-temporal information and the support of multi-scale geographic databases, where objects are represented at many different resolution levels

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