COSIT 2011 Tutorial, Belfast, Maine, 12th-16th September, 2011 Exploring the Place of Vagueness in Spatial Information Brandon Bennett, University of Leeds, UK Pragya Agarwal, Lancaster University, UK

Natural language descriptions of the world are pervasively affected by vagueness. Our ordinary use of concepts and relationships is not prescribed by rigid rules but rather is flexible, adaptable and subject to interpretive differences and controversies. This vagueness is apparent in a wide variety of spatial concepts and relations and also affects the spatial extension ascribed to geographic features and other referents.

The use of vague concepts is usually harmless and often very useful. They allow us to convey information without the need to provide precise and unnecessary details. However, in the context of representation and processing of spatial information, the presence of vagueness is highly problematic. Conventional data structures and processing algorithms assume that information has a definite meaning and cannot be easily adapted to handle vague concepts. And despite the current development of sophisticated spatial and geographic ontologies these problems persist (in fact it may be argued that the construction of ontologies makes the presence of vagueness even more apparent and problematic). The tutorial will examine the many difficulties that arise from vagueness in spatial information and explore some of the more promising approaches to solving them.

The representation of "place" is a secondary theme of the tutorial, which is closely connected to the main theme of vagueness. The notion of "place" is central to human understanding of space, and yet its status with respect to formalised representations of spatial information is elusive. The slipperiness of "place" arises partly due to vagueness in the descriptions used to identify places, partly from the lack of any consensus as to what formal syntax and semantics can adequately capture concepts of place, and partly due to ambiguity in the very notion of "place". These issues will be explored from both a logical and a social perspective.

• Introduction to Vagueness in Spatial Information (Bennett)
  • The problem of vagueness.
  • Approaches to representation and reasoning the presence of vagueness.
    • Fuzzy Logic
    • Supervaluation Semantics
    • Standpoint Semantics
  • Vagueness in Spatial Information
  • Handling Vagueness in Spatial and Geo-Spatial Ontologies

• The Place of Vagueness in Socially Constructed Geography (Agarwal)
  The recent development of interactive technologies for enabling diverse users to participate in the creation of geographic information presents new challenges for the structuring and interpretation of geographic data: issues of vagueness, variability of meaning and the ambiguity of "place" terms are brought to the fore and can no longer be hidden behind the cartographic conventions of traditional maps.

• Vagueness of Geographic Feature Terms. (Bennett and Agarwal)
  Facilitated group discussions.
  A number of different geographic feature types will be considered in detail (including hydrographic features, vegetation cover, deserts and landforms), with the aim of developing formal representations that can be used not only to define and reason about them, but also to automatically detect instances of these features on the basis of geographic data. It will be seen that characterising these features requires both a rich ontology of geometric and physical properties and relationships and also apparatus to account for the variability in the meanings of geographic terms due to their inherent vagueness.

• The semantics of "place" (Agarwal and Bennett)
  The idea of "place" is central to our conception of space and yet there is little consensus on what role it should play within spatial information systems, and its representation in logical formalisms remains elusive. We shal consider the following aspects of "place" and its relation to spatial information.
  • Commonsense understanding of "place" (Agarwal)
  • The logical status of "place" (Bennett)
  • Sense of Place (Agarwal)

The slides presented at the tutorial are available HERE.

The Organisers

Brandon Bennett Institute for Artificial Intelligence and Biological Systems School of Computing University of Leeds Leeds , LS2 9JT, UK. Brandon Bennett has published extensively on many aspects of knowledge representation and reasoning. He has focused in particular on spatial reasoning, representation of events, geographic and environmental ontologies and the semantics of vagueness. He has also worked with Pragya Agarwal on semantic analysis of the conept of "place".

Pragya Agarwal Reader in Design: Spaces and Places Lancaster Institute for the Contemporary Arts Lancaster University Lancaster, UK Pragya Agarwal's research spans theoretical and analytical issues in GIScience, including geographic ontologies and semantic interoperability, spatio-temporal cognition and reasoning, process modelling and behavioural dynamics, usability and knowledge capture, and Personalised Geospatial Services and Systems.