A framework for evaluating geographical information

This paper introduces a framework for the evaluation of geographic information (GI), divided into representational and communicative aspects. The representational component is concerned with how ‘real-world’ phenomena situated in space and time come to be represented or modelled in GI, considered at ontological, modelling and system levels. The communicative component of GI is concerned with how representations of GI are understood by the users of the information, considered at relevance, commodification, exploration and management levels. This paper attempts to bring together the previous work in all these areas into an evaluative framework so that creators and users can assess the validity and success of the representational and communicative process overall. This paper also outlines the architecture of a client-server geolibrary designed for information sharing. This kind of architecture provides a distributed and open platform for the development of GI networks, upon which more productive use of GI can be built in future. Introduction Geographic information (GI) is defined by the use of spatial and temporal referencing to characterise information. Represented using paper maps and gazetteers for millennia, GI can now be represented digitally as imagery, terrain models, mapping, databases or multimedia, and takes the form of a geometrically structured aggregation of elements. The scope, volume and diversity of GI now means that structuring, managing and accessing GI has become a complex and demanding task. Despite this complexity, there are few models or frameworks for the evaluation of GI collections. This paper aims to draw together the theoretical foundations and to show how work in the City University Geographical Information Science Group (GISG) has offered some practical solutions to the challenges of structuring GI collections and facilitating GI access and sharing. Like information generally, GI can be said to have a representational component and a communicative component, although they are reflexively connected. Representation is defined here as the projection of the entities, relationships and processes of the conceptualised world onto symbolic 'facsimile' objects and models with their associations and transformations. The representational component is concerned with how ‘real-world’ phenomena situated in space and time come to be represented or modelled in GI (Raper 2000a). The most common systems designed to handle GI are geographical information systems (GIS), which use georeferencing techniques to tie the GI to the earth and geometric techniques to represent the phenomena. However, a wide range of other applications have now been developed to handle forms of GI including image processors, terrain modelling tools, navigation and mapping systems, spatio-temporal databases, spatial multimedia applications, virtual reality systems, address management tools and simulation models. These applications have evolved a wide range of ‘georepresentations’ that have been integrated into methodological processes associated with a variety of disciplines such as geography, planning, landscape architecture, earth science and archaeology. This paper will identify the key representational processes that are used to produce GI collections. The communicative component of GI is concerned with how representations of GI are understood by the users of the information (MacEachren 1995). Aspects of information understanding can be found in cognition and linguistics, in disciplinary practices, and in the information seeking and retrieval process. Communication of GI is a coupled and reflexive process involving the creator and the user. At present, creators of GI tend to assume that users have access to the methodological processes that gave rise to the geo-representation even though that it is usually not the case. The relatively recent use of highly interactive graphics to foster ideation during exploratory analysis is termed ‘visualization’. Geovisualization is an evolving field that incorporates these techniques with cartography to apply them to spatial information (MacEachren and Kraak, 2001). Users employ conjectural geovisualization processes to explore GI for structure, pattern and associations among the aggregation of elements making it up. Maps can also be used to confuse and mislead as Monmonier (1991) has shown in ‘How to lie with maps’. This paper will explore the communicative processes employed in the use of GI. Evaluation of GI depends on an assessment of both representational and communicative components, and the ways that they interact. While there has been substantial previous work on distinct aspects of the representational and communicative components (Raper 2000a), they have not been brought together into any kind of overall evaluative framework. Yet such a synthesis is required to allow creators and users to assess the validity and success of the representational and communicative process overall. The development of an evaluative overview of GI also promotes new modes for the use of GI: hence, in addition to the production and consumption of GI it becomes possible to share GI with a mutual understanding of its origins and value. The representational component of GI Representation of GI can be organised at three levels for evaluation: an ontological level at which the definition of geo-phenomena as geographic entities are considered; a modelling level at which geographic entities are defined as GI; and, a system level at which GI is implemented in software terms as geo-representations. Use of this template will allows a user of GI to assess its representational origins, and thus to evaluate its suitability for a given purpose.