| |  | Jensen, Christian S. | A Conceptual Schema Language for the Management of Multiple Representations of Geographic Entities read moreAbstract: Multiple representation of geographic information occurs when a real-world entity is represented more than once in the same or different databases. This occurs frequently in practice, and it invariably results in the occurrence of inconsistencies among the different representations of the same entity. In this paper, we propose an approach to the modeling of multiple represented entities, which is based on the relationships among the entities and their representations. Central to our approach is the Multiple Representation Schema Language that, by intuitive and declarative means, is used to specify rules that match objects representing the same entity, maintain consistency among these representations, and restore consistency if necessary. The rules configure a Multiple Representation Management System, the aim of which is to manage multiple representations over a number of autonomous federated databases. We present a graphical and a lexical binding to the schema language. The graphical binding is built on an extension to the Unified Modeling Language and the Object Constraint Language. We demonstrate that it is possible to implement the constructs of the schema language in the object-relational model of a commercial RDBMS. | 2005 |
| | | Worboys, Michael | Event-oriented approaches to geographic phenomena read moreAbstract: This paper is about the information-theoretic foundations upon
which useful explanatory and predictive models of dynamic geographic
phenomena can be based. It traces the development over the last
decade or so of these foundations, from sequences of temporal snapshots,
through object life histories, to event chronicles. A crucial ontological
distinction is drawn between “things” and “happenings”, that is
between continuant and occurrent entities. Most of the work up to now
has focused on representing the evolution through time of geographic
things, whether objects or fields. This paper argues that happenings
should be upgraded to an equal status with things in dynamic geographic
representations, and suggests ways of doing this. The main
research focus of the paper is the application of an algebraic approach,
previously developed mainly in the context of computational processes,
to real-world happenings. It develops a pure process theory of space
and time, and demonstrates its applicability by providing an example
of the representation of motion of a vehicle through a region. The
paper concludes by noting some of the requirements for scaling this
approach to real-world dynamic scenarios, such as might be found, for
example, in the automation of coordination of disaster relief. | 2005 |
| | | Grenon, Pierre | SNAP and SPAN: Towards Dynamic Spatial Ontology read moreAbstract: We propose a modular ontology of the dynamic features of reality. This
amounts, on the one hand, to a purely spatial ontology supporting snapshot views of the world at successive instants of time and, on the other hand, to a purely spatiotemporal ontology of change and process. We argue that dynamic spatial ontology must combine these two distinct types of inventory of the entities and relationships in reality, and we provide characterizations of spatiotemporal reasoning in the light of the interconnections between them. | 2004 |
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