Location-based services and GIS in perspective

This paper examines location-based services (LBS) from a broad perspective involving deWnitions, characteristics, and application prospects. We present an overview of LBS modeling regarding users, locations, contexts and data. The LBS modeling endeavors are cross-examined with a research agenda of geographic information science. Some core research themes are brieXy speculated

Spatial queries with qualitative locations in spatial information systems

We discuss locations as defined by their qualitative spatial relations to other features, dubbed qualitative locations (QL). We further propose a mechanism to handle queries with qualitative locations in geospatial information systems. For the realization of the mechanism for QL-based queries, we propose a conceptual framework that takes advantage of models of qualitative spatial reasoning to bridge the gap between conventional metric spatial information systems and the general publicÕs common-sense query of spatial relations in natural language. Ó 2004 Published by Elsevier Ltd