The availability of map interfaces and location-aware devices makes a growing amount of unstructured, geo-referenced information available on the Web. This type of information can be valuable not only for browsing, finding and making sense of individual items, but also in aggregate form to help understand data trends and features. In particular, over twenty million geo-referenced photos are now available on Flickr, a photo-sharing website – the first major collection of its kind. These photos are often associated with userentered unstructured text labels (i.e., tags). We show how we analyze the tags associated with the geo-referenced Flickr images to generate aggregate knowledge in the form of “representative tags ” for arbitrary areas in the world. We use these tags to create a visualization tool, World Explorer, that can help expose the content of the data, using a map interface to display the derived tags and the original photo items. We perform a qualitative evaluation of World Explorer that outlines the visualization’s benefits in browsing this type of content. We provide insights regarding the aggregate versus individual-item requirements in browsing digital geo-referenced material.

Geographic interfaces provide natural, scalable visualizations for many digital library collections, but the wide range of data in digital libraries presents some particular problems for identifying and disambiguating place names. We describe the toponym-disambiguation system in the Perseus digital library and evaluate its performance. Name categorization varies significantly among di#erent types of documents, but toponym disambiguation performs at a high level of precision and recall with a gazetteer an order of magnitude larger than most other applications.

Geographical context is required of many information retrieval tasks in which the target of the search may be documents, images or records which are referenced to geographical space only by means of place names. Often there may be an imprecise match between the query name and the names associated with candidate sources of information.

This paper combines spatial hypermedia with techniques from Geographical Information Systems and location based services. We describe the Topos 3D Spatial Hypermedia system and how it has been developed to support geospatial hypermedia coupling hypermedia information to model representations of real world buildings and landscapes. The prototype experiments are primarily aimed at supporting architects and landscape architects in their work on site. Here it is useful to be able to superimpose and add different layers of information to, e.g. a landscape depending on the task being worked on. We introduce a number of central concepts to understand the relation between hypermedia and spatial information management. The distinction between metaphorical (and abstract) versus literal (and concrete) spaces is introduced together with a workspace composition semantics and a distinction between direct and indirect navigation. Finally, we conclude with a number of research issues which are central to the future development of geo-spatial hypermedia, including design issues in combining metaphorical and literal hypermedia space, as well as a discussion of the role of spatial parsing in a geo-spatial context.

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Abstract. Geographical information exists in multiple forms such as cartographical maps, images, and texts. Effective retrieval systems for geographical information are currently studied by both geospatial information scientists and library/information scientists. The two groups take quite different approaches which have rarely been explicitly compared and connected. This paper discusses the advantages and limitations of current geographical information retrieval (GIR) and textual information retrieval (IR) systems in dealing with multimedia geographical information, and proposes a new retrieval model, called GeoVSM (Geographical + Vector Space Model), which integrates coordinate-based geographical indexing with keyword-based vector space model in representing information space. Document ranking by relevance is supported by document-query similarity measure taking into account degree of relevance in both spatial domain and thematic domain. To support visual query and browsing, GeoVSM model recognizes the fundamental differences in the dimensionality and configuration of geographical space and thematic space, and demands multi-view visual interfaces based on a “world ” metaphor and a “desktop ” metaphor. As an example of such interfaces, GeoVIBE is presented that supports a coordinated GeoView and a VibeView for smooth integration of two browsing strategies using geographic clues as well as thematic clues provided by users. 1.

Gazeteers and geographical thesauri can be regarded as parsimonious spatial models that associate geographical location with place names and encode some semantic relations between the names. They are of particular value in processing information retrieval requests in which the user employs place names to specify geographical context. Typically the geometric locational data in a gazetteer are confined to a simple footprint in the form of a centroid or a minimum bounding rectangle, both of which can be used to link to a map but are of limited value in determining spatial relationships. Here we describe a Voronoi diagram method for generating approximate regional extents from sets of centroids that are respectively inside and external to a region. The resulting approximations provide measures of areal extent and can be used to assist in answering geographical queries by evaluating spatial relationships such as distance, direction and common boundary length. Preliminary experimental evaluations of the method have been performed in the context of a semantic modelling system that combines the centroid data with hierarchical and adjacency relations between the associated place names.

This paper explores the possibilities of visualizing document similarities and differences in both spatial and topical domains. Building on previous studies of geographical information retrieval and textual information retrieval (IR) systems, we report on the development of an information browsing tool, GeoVIBE. The system consists of two types of browsing windows, GeoView and VibeView, that work in coordination for visual navigation in the document space. GeoView imposes a geographical order to the document space based on the idea of hypermaps where "icons" and "footprints" may be embedded in maps as the clickable hotspots linking to relevant documents.

Abstract: This paper surveys research areas relevant to cultural

Geographic information retrieval is a new and evolving domain. The development of GIR systems requires the analysis of requirements for such systems and, after systems are implemented their evaluation. This paper describes requirement analysis and evaluation for the SPIRIT system. Methods of user and system-centred evaluation are described and a methodology for building a document collection to facilitate derivation of measures of system performance, together with a new scheme for the evaluation of spatial and thematic relevance with respect to search results are introduced. The paper stresses the importance of developing approaches to evaluate GIR systems which holistically evaluate user interactions as well as measures of system performance.