Landmarks are significant in one’s formation of a cognitive map of both physical environments and electronic information spaces. Landmarks are defined in physical space as having key characteristics that make them recognizable and memorable in the environment. The challenge of defining measurable features of landmarks that can be used in designing and recognizing landmarks in information spaces is explored. By drawing on diverse areas such as urban planning, architecture, cognitive science and hypertext, a coherent definition of a landmark is proposed, which is relevant to both physical and electronic spaces. It is argued that landmarks can be classified in terms of visual, cognitive and structural dimensions, which has implications for how environments can be designed or built in such a way that landmarks will emerge appropriately for unique situations.

An increasing number of tasks require people to explore, navigate and search extremely complex data sets visualized as graphs. Examples include electrical and telecommunication networks, web structures, and airline routes. The problem is that graphs of these real world data sets have many interconnected nodes, ultimately leading to edge congestion: the density of edges is so great that they obscure nodes, individual edges, and even the visual information beneath the graph. To address this problem we developed an interactive technique called EdgeLens. An EdgeLens interactively curves graph edges away from a person’s focus of attention without changing the node positions. This opens up sufficient space to disambiguate node and edge relationships and to see underlying information while still preserving node layout. Initially two methods of creating this interaction were developed and compared in a user study. The results of this study were used in the selection of a basic approach and the subsequent development of the EdgeLens. We then improved the EdgeLens through use of transparency and colour and by allowing multiple lenses to appear on the graph.

A method is described for visualizing the contents of a Web site with a hierarchical table of contents using a Java program and applet called WebTOC. The automatically generated expand/contract table of contents provides graphical information indicating the number of elements in branches of the hierarchy as well as individual and cumulative sizes. Color can be used to represent another attribute such as file type and provide a rich overview of the site for users and managers of the site. Early results from user studies suggest that WebTOC is easily learned and can assist users in navigating websites. Keywords: Information Visualization, Exploratory Data Analysis, Graphical Representations, Hierarchical Table of Contents, Java applet, World Wide Web, Browsing. * Mr. Nation was a visiting researcher at the University of Maryland when the work was performed. This paper represents the views of David Nation and not necessarily those of the DoD. Introduction One difficulty in information vis...

For many purposes, the Web page is too small a unit of interaction and analysis. Web sites are structured multimedia documents consisting of many pages, and users often are interested in obtaining and evaluating entire collections of topically related sites. Once such a collection is obtained, users face the challenge of exploring, comprehending, and organizing the items. We report four innovations that address these user needs. . We replaced the web page with the web site as the basic unit of interaction and analysis. . We defined a new information structure, the clan graph, that groups together sets of related sites. . We augment the representation of a site with a site profile, information about site structure and content that helps inform user evaluation of a site. . We invented a new graph visualization, the auditorium visualization, that reveals important structural and content properties of sites within a clan graph. Detailed analysis and user studies document the utility o...

This paper focuses on the representation and access of Web-based information, and how to make such a representation adapt to the activities or interests of individuals within a community of users. The heterogeneous mix of information on the Web restricts the coverage of traditional indexing techniques and so limits the power of search engines. In contrast to traditional methods, and in a way that extends collaborative filtering approaches, the path model centres representation on usage histories rather than content analysis. By putting activity at the centre of representation and not the periphery, the path model concentrates on the reader not the author and the browser not the site. We describe metrics of similarity based on the path model, and their application in a URL recommender tool and in visualising sets of URLs.

A major problem for users of modern information systems is the retrieval of new and previously viewed information from the system. Systems like the Word-Wide Web are heavily interlinked but do not communicate structure that helps users to navigate the information it contains. The use of appropriate navigation metaphors can help to make the structure of modern information systems easier to understand, and therefore, easier to use. We propose a conceptual user interface metaphor based on the structure of a city. Cities are very complex spatial environments and yet, people are used to navigating within cities. They know how to get information, how to reach particular destinations, and how to make use of the infrastructure. Furthermore, cities possess a unique set of navigational tools that lend themselves to creating sub-metaphors. A city metaphor makes this existing knowledge about a structured environment available to the user of a computerized information system. In this paper, we fi...

This paper describes a generic approach to structuring and visualising a hypertext-based information space on the WWW. This approach, called Generalised Similarity Analysis (GSA), provides a unifying framework for extracting structural patterns from a range of proximity data concerning three fundamental relationships in hypertext, namely, hypertext linkage, content similarity and browsing patterns. GSA emphasizes the integral role of users' interests in dynamically structuring the underlying information space. Pathfinder networks are used as a natural vehicle for structuring and visualising the rich structure of an information space by highlighting salient relationships in proximity data. In this paper, we use the GSA framework in the study of hypertext documents automatically retrieved over the Internet, including a number of departmental WWW sites and conference proceedings on the WWW. We show that GSA has several distinct features for structuring and visualising hyp...

The World-Wide Web is becoming an invaluable source for the information needs of many users. However, current browsers are still primitive, in that they do not support many of the navigation needs of users, as indicated by user studies. They do not provide an overview and a sense of location in the information structure being browsed. Also they do not facilitate organization and filtering of information nor aid users in accessing already visited pages without high cognitive demands. In this paper, a new browsing interface is proposed with multiple hierarchical windows and efficient multiple window operations. It provides a flexible environment where users can quickly organize, filter, and restructure the information on the screen as they reformulate their goals. Overviews can give the user a sense of location in the browsing history as well as provide fast access to a hierarchy of pages.

By virtue of their spatio-cognitive abilities, humans are able to navigate through geographic space as well as meaningfully communicate geographic information represented in cartographic form. The current dominance of spatial metaphors in information visualization research is the result of the realization that those cognitive skills also have value in the exploration and analysis of nongeographic information. While mapping or landscape metaphors are routinely used in this field, there is a noticeable lack of consideration for existing cartographic expertise. This is especially apparent whenever problematic issues are encountered, such as graphic complexity or feature labeling. There are a number of areas in which a cartographic outlook could provide a valuable perspective. This paper discusses how geographic and cartographic notions may influence the design of visualizations for textual information spaces. Map projections, generalization, feature labeling and map design issues are disc...

This paper presents two hyperlink analysis-based algorithms to find relevant pages for a given Web page (URL). The first algorithm comes from the extended cocitation analysis of the Web pages. It is intuitive and easy to implement. The second one takes advantage of linear algebra theories to reveal deeper relationships among the Web pages and to identify relevant pages more precisely and effectively. The experimental results show the feasibility and effectiveness of the algorithms. These algorithms could be used for various Web applications, such as enhancing Web search. The ideas and techniques in this work would be helpful to other Web-related researches.