Visualizing Geospatial Information Uncertainty: What We Know and What We Need to Know
Alan M. MacEachren, Anthony Robinson, Susan Hopper, Steven Gardner, Robert Murray, Mark Gahegan, and Elisabeth Hetzler

Developing reliable methods for representing and managing information uncertainty remains a persistent and relevant challenge to GIScience. Information uncertainty is an intricate idea, and recent examinations of this concept have generated many perspectives on its representation and visualization, with perspectives emerging from a wide range of disciplines and application contexts. In this paper, we review and assess progress toward visual tools and methods to help analysts manage and understand information uncertainty. Specifically, we report on efforts to conceptualize uncertainty, decision making with uncertainty, frameworks for representing uncertainty, visual representation and user control of displays of information uncertainty, and evaluative efforts to assess the use and usability of visual displays of uncertainty. We conclude by identifying seven key research challenges in visualizing information uncertainty, particularly as it applies to decision making and analysis. Keywords: Uncertainty, geovisualization, representation, decision making, usability

Assessment of Simulated Cognitive Maps: The Influence of Prior Knowledge from Cartographic Maps Robert Earl Lloyd

Real cognitive maps encoded by humans are difficult to study using experimental methods because they are a product of complex processes whose content and timing cannot easily be known or controlled. This paper assesses the value of using neural network model simulations for investigating cognitive maps. The study simulated the learning of mapped city locations in South Carolina from reference sites in the three primary regions of the state using Kohonen self-organizing maps. The learning performances of models were considered based on available prior knowledge. Bi-dimensional regression analyses were used to assess the congruity of the simulated cognitive maps with a cartographic map and with sketch maps produced by human subjects. Error analyses indicated differences between central and peripheral reference sites. The cities known by subjects living at a central location were more evenly distributed in space and associated with significantly smaller errors. Models that learned combined state boundary and interstate highway information as prior knowledge or simultaneously with city locations consistently produced the best simulation results. The results indicated simulated cognitive maps could be used effectively to study the acquisition of spatial knowledge. Keywords:  Cognitive maps, simulations, sketch maps, spatial learning, self-organized maps  

System Design Considerations for the Development of an Electronic Statistical Atlas

Lysandros Tsoulos

In the recent history of cartography, atlases deserve a prominent status among cartographic products due to the variety of their thematic content, the rather friendly appearance and their utilization by a wide spectrum of users. Advances in information technology, and more specifically in geographic information systems and digital mapping, have altered the fundamental way of using maps, and thus they have a major impact on every aspect of electronic atlas design and development.  Although considerable effort has been made towards the production of electronic atlases, and successful systems are available, there are still a number of factors that must be considered towards the improvement of their design and functional characteristics. This paper elaborates on those factors and suggests a specific approach toward the design and development of electronic atlases, particularly electronic statistical atlases. This approach has been used for the development of the Statistical Atlas of the European Union (STATLAS_EU), which is intended to provide a user-friendly resource for statistical analysis.

KEYWORDS: Electronic atlas, atlas design and development, graphic user interface (GUI), open source software, Extended Mark-up Language (XML), Geography Mark-up Language (GML)

Creating Buffers on Surfaces

 Xingong Li, Christopher M. Larson, and Arthur B. Rex

 Creating buffers is an important function used in geographic information systems (GIS) to perform spatial analysis. However, delineating buffers for setbacks in conservation and planning applications is problematical in mountainous areas. A typical vector buffer function in GIS calculates two-dimensional (2D) Euclidean distance (i.e., planimetric distance) instead of surface (or slope) distance and results in an inaccurate representation of buffers when they are verified in the field. A method of delineating buffers on surfaces in the raster data model is presented in this paper. An efficient implementation of the method is achieved through the use of a min-heap and a hash-table based location index. The method is tested and analyzed on both hypothetical and real surface datasets.