Vague Spatio-Thematic Query Processing: A Qualitative Approach to Spatial Closeness

Abstract

In order to support the processing of qualitative spatial queries, spatial knowledge must be represented in a way that machines can make use of it. Ontologies typically represent thematic knowledge. Enhancing them with spatial knowledge is still a challenge. In this article, an implementation of the Region Connection Calculus (RCC) in the Web Ontology Language (OWL), augmented by DL-safe SWRL rules, is used to represent spatio-thematic knowledge. This involves partially ordered partitions, which are implemented by nominals and functional roles. Accordingly, a spatial division into administrative regions, rather than, for instance, a metric system, is used as a frame of reference for evaluating closeness. Hence, closeness is evaluated purely according to qualitative criteria. Colloquial descriptions typically involve qualitative concepts. The approach presented here is thus expected to align better with the way human beings deal with closeness than does a quantitative approach. To illustrate the approach, it is applied to the retrieval of documents from the database of the Datacenter Nature and Landscape (DNL).

Rewriting Queries for Web Searches That Use Local Expressions

“…In the context of this paper, CL(x, y), which is read as "x is close to y", is introduced as a weakly asymmetrical relation, in accordance with empirical evidence [9]. Against the background of knowledge considered in this paper, this means that the relation is usually symmetrical, if x and y are members of the same administrative partition (e.g., both are communities), but asymmetrical, if y is a member of a more fine-grained partition than x (e.g., y is a community and x a district) or else, if x is a nonadministrative region.…”

“…Query concepts can, thus, be used to determine the scale on which spatial relations are to be . 9 Note that partOf(a i , b j ) and the roles subsumed by partOf(a i , b j ) are used for asserting partitions into administrative regions only evaluated. For the evaluation (cf.…”

DC Proposal: Towards a Framework for Efficient Query Answering and Integration of Geospatial Data

“…Besides having rules to formalize spatial integrity constraints [1], rules opens a way to qualitative spatial reasoning with the Region Connection Calculus (RCC) being applied on top of ontologies and spatial data [15]. Several authors have considered these combinations.…”

“…We distinguish between heterogeneous and homogeneous combinations, where heterogeneous combinations can be separated into loose couplings and tight integrations. Grütter et al focus on enhancing ontologies with spatial reasoning based on RCC and SWRL-rules to capture dependencies between different administrative regions [15]. In [1], a combined framework based on Description Logic Programs (DLP) was introduced.…”

“…Finally, in the work of Grütter et al a web search is enhanced with DL and spatial reasoning based on RCC8. RCC8 is encoded in SWRL-rules to capture spatial dependencies between different administrative regions [15].…”