Ontology‐Based Metadata

Abstract

It is even more remarkable to some of us that up to this point, there has been no thoroughgoing discussion by GIS practitioners and theorists about the epistemology of their subject, the ontology of their objects, and the political commitments embedded in their practices.(Pickles 1997, p. 364) Abstract Metadata are an extant mechanism for conveying ontological information about semantic data. Metadata have the advantage of being institutionally and structurally ensconced in GIS. At present, however, they lack fields to express information beyond the technical and geometric domain. This paper describes a framework for the creation of extended metadata for non‐spatial attributes, with the goal of incorporating ontological context. We use an informatics interpretation of ontology which refers to the total universe of discourse associated with a given attribute (database field). In other words, an ontology is the possible range of meaning offered by an encoded field. Current ontology research in GIScience has focused on data structuring and modelling. Implementation of these schemes demands restructuring of existing relational database models. An alternative is to extend current metadata schemes (e.g. ISO 19115) to include context‐based and tacit information about semantic attributes. Such ontology‐based extended metadata permits data selection and interoperability decisions that are ultimately more defensible. We have developed eight preliminary fields to add to existing metadata frameworks that will enable ontological context to travel with the data. This paper illustrates a preliminary implementation based on the integration of non‐commensurate cadastral data. The results illustrate the value of ontology‐based metadata in highlighting descriptive and substantive differences between similar classification systems. Recognition of semantic heterogeneity is the basis for creating defensible data linkages between multiple datasets. The development of ontology‐based metadata is profoundly different from the current trend to incorporate ontological context at the model level in GIScience. It is pragmatic, however, in that it presents a vehicle for incorporating use‐context with data in a manner that is accessible; requires little re‐engineering; and is intuitively understood by GIS users. Moreover, ontology‐based metadata are a mechanism for addressing Pickles’ (1997) concern about the ontology of spatial objects in GIS.

Volunteered geographic information: future research directions motivated by critical, participatory, and feminist GIS

“…As well, we may wish to consider whether the data structures and visualization services commonly used with VGI are able to store or communicate anything about the situated context in which volunteered information was generated. Schuurman and Leszczynski (2006) and others have illustrated that such details about the context of spatial knowledge production (and its representation as digital data) are centrally important to understanding the data themselves and their societal applications and impacts. The situated nature of spatial knowledge is also important to questions of accuracy and reliability in volunteered information.…”

“…For instance, consider the expressed concerns about ensuring consistency and reliability in volunteered information. Research on SDIs, data standards, and metadata standards has well documented that these existing structures are quite limited in their capacity to foster consistence in traditionallyconceived and managed spatial data (Nedovic-Budic et al 2004;Onsrud et al 2005;Schuurman and Leszczynski 2006). The potential heterogeneity of VGI and the openness of many platforms for collecting and visualizing it may mean that existing structures and practices for ensuring spatial data consistency and completeness are even less appropriate in this context.…”

A Unified Approach for Spatial Data Query

“…In [10], an approach to analyze geographic metadata for information search is introduced. In [11], the shortcomings of conventional approaches to semantic data integration and of existing metadata frameworks are discussed. On the other hand, the problem of vector and raster data integration was also investigated.…”

Geospatial Web Services for Environmental Planning

“…Collaborative GIS have been used in many planning problems for solving semi-structured or loosely structured decision problems in environmental planning (Angelides and Angelides 2000;Balram and Dragic´evic 2006;Balram, Dragicevic and Meredith 2003;Kingston, Carver, Evans and Turton 2000) The Web GIS implementation area mainly includes environmental planning (Sikder and Gangopadhyay 2002;Tuchyna 2006), data dissemination (Hu 1999;Schuurman andLeszczynski 2006), community planning (Al-Kodmany 2000;MacEachren, Pike, Yu, Brewer, Gahegan, Weaver and Yarnal 2006;Rao, Fan, Thomas, Cherian, Chudiwale and Awawdeh 2007). While researchers continue to argue for an integration and structuring of collaborative mapping and visualization technologies into spatial decision making (Armstrong 1994;Balram and Dragic´evic 2006;Jankowski and Nyerges 2001;MacEachren 2001;Nyerges and Jankowski 2001), a Web-based GIS framework designed to integrate stakeholders into the planning process has yet to be realized.…”