2002): Toward a Geospatial Data Infrastructure for Northrhine-Westphalia. Computer, Environment and Urban Systems 26

with many numerous European, North American, and Australian experts have helped to shape the ideas expressed. A better exploitation of existing geographic information through intelligent services for citizens, professionals, and decision-makers is urgently needed. The project for a Geospatial Data Infrastructure in Northrhine-Westphalia targets such an improvement by establishing the means for an expansion of markets for geographically related information products and services. This overall objective will be reached by an interdisciplinary approach of institutional, commercial, and research organizations in the GI-market. The Institute for Geoinformatics, University of Muenster, contributes the design of an overall service architecture and a systematic analysis of underlying research questions. A reference model provides the framework for design, communication, and a consensus process amongst the project partners. We present here a first overview of the chosen goals and strategies. Keywords: geographic information infrastructures, GDI-NRW, information products, business networks, reference model, standard

Semantic interoperability: A central issue for sharing geographic information

Technical interoperability has provided geographic information communities with substantial improvements for constructing GIS capable of very low friction and dynamic data exchanges. These technical advances stand to provide substantial advantages for sharing geographic information, however reaping these advantages in highly heterogeneous operational and organizational environments requires the understanding and resolution of semantic differences. While the OpenGIS consortium has made important progress on technical interoperability, semantic interoperability still remains an unpassed hurdle for efforts to share geographic information across organizational and institutional boundaries at the local, regional, and other levels. Identifying and resolving semantic interoperability issues is especially pertinent for data sharing and considering future developments of standards. This paper presents an overview of semantic interoperability and through case studies shows the breadth and depth of issues and approaches in different countries and at different levels of organizations. These cases illustrate the importance of developing flexible approaches to practical data sharing problems that merge semantical with technical considerations. Based on our examinations of semantic issues and approaches in ongoing research projects, we propose cognitive, computer science, and socio-technical frameworks for examining semantic interoperability.

What a geographical entity could be

The main task of this article is providing a sketch of possible approaches, response attempts, conundrums and issues arising from the question: 'What is a geographical entity?'. It is shown how trying to answer this question is made particularly difficult by a multiplicity of aspects that might be summarized as follows: (1) There exist multiple conceptualizations of the geographical world. (2) Different languages and cultures may slice such a world in different ways. (3) The geographical world has changed and will change over time. (4) Also geography (as a discipline) has changed and will change over time, modifying its perspective, tools, domains of investigation and aims. Consequently, what had, has been, will be considered as non-geographic could be considered as geographic and vice versa. (5) There were, are and will be different kinds of geographies as well as different geographical branches, each of them had, have and might have different tools, aims, points of view and vocabularies. (6) The introduction of new scholarly fields and new technologies, the birth of intellectual movements or paradigm shifts and developments on other disciplinary contexts can/will influence geography as a discipline