Welcome to this theme issue on exploring geovisualization. Here, we focus on some of the methods, processes, and collaborations involved with visualizing geographic information and geospatial data. The authors present approaches that encompass information and scientific visualization techniques as well as methods developed in cartography and geographic information science. For more than two decades, the cartographic, geographic information system (GIS), and visualization communities have worked in closely related yet arguably independent disciplines. In this theme issue, we focus on the cross-disciplinary connections that facilitate the visual display and interactive exploration of geospatial data and the information derived from it.
Our efforts are the result of a decade's worth of collaboration among the
• ACM Siggraph Carto Project ( http://www.siggraph.org/~rhyne/carto/),
• International Cartographic Association's Commission on Visualization and Virtual Environments ( http://www.kartografie.nl/icavis/), and
• Web3D Consortium's X3D GeoSpatial Working Group ( http://www.web3d.org/x3d/workgroups/geospatial/).
Since the ACM Siggraph Carto Project began in 1996, birds-of-a-feather (BOF) sessions at the annual Siggraph conference have brought these groups together. In that time frame, the Web3D Consortium released GeoVRML Open Source Code ( http://www.geovrml.org/1.1/doc/) that is now modified and included in the X3D standard while the ICA Commission on Visualization and Virtual Reality released a research agenda for geovisualization ( http://www.kartografie.nl/icavis/agenda/index.html). The ACM Siggraph Carto BOF sessions have also featured emerging technologies that resulted in applications like Google Earth ( http://earth.google.com/) and similar Web-based services.
Building on the past work, in spring 2005, we issued a call for contributions to this issue on geovisualization. We received 40 inquiries about submission and at the submission deadline had 22 completed papers. For each submission, we assigned two reviewers: one from the computer graphics/visualization community and another from the cartography/geographic information systems community. We also provided our own editorial comments and suggestions. The reviews and our editorial commentaries were completed in mid-November 2005. We accepted five papers and recommended revisions and other publication venues for many of the other papers. This review process was demanding and we are appreciative to the 40 or so academic colleagues who participated. We are thrilled to present five articles that are indicative of the broad range of applications and future directions in geovisualization.
In the first article, "MapShaper.org: A Map Generalization Web Service," Harrower and Bloch discuss the development of an online map generalization application constructed in Macromedia Flash and available remotely through a Web browser. In cartography, the practice of generalization involves conceptualizing important features and employing graphic symbols to synthesize salient information on a map. Harrower and Bloch present an interactive tool for automatically addressing generalization problems for on-demand mapping services.
The second article presents GIS science perspectives on developing 3D Web-based visualization tools. "Web-Based Visualization of 3D Geospatial Data Using Java3D" by Hobona, James, and Fairbairn describes a prototype system for integrating varied database servers with 3D spatial data visualization techniques. Their Geospatial Database Online Visualization Environment (GeoDOVE) supports mappings between the Open Geospatial Consortium Simple Features geometry and Java3D geometry structures.
In "The Distance-Similarity Metaphor in Region-Display Spatializations," Fabrikant, Montello, and Mark report on two experiments they conducted on people's ability to interpret region-based spatializations or map-like displays of nongeographic information. This investigation addresses color-hue effects and treemap elements. The authors' evaluative research offers experimental evidence to support the appropriate use of traditional cartographic design principles in information visualization problems.
Forsberg et al.'s article, "Adviser: Immersive Field Work for Planetary Scientists," introduces five case studies where a scientific visualization/VR environment was accessed to examine remote locations like Antarctica, Mars, and other future NASA planetary missions. Their Advanced Visualization in Solar System Exploration and Research (Adviser) system operates in a Cave—a four-wall surround-screen, surround-sound, projection-based VR system. Adviser lets geoscientists view multiple scientific data sets of topographic information, virtually perform quantitative measurements of strata geometry, and conceptualize complex 3D relationships in remote and inaccessible locations.
Finally, "Real-Time Landscape Model Interaction Using a Tangible Geospatial Modeling Environment" by Mitasova et al. describes interaction with geospatial data through the creative coupling of an open source GIS tool and a 3D physical modeling system. This emerging technology lets users modify the surface model by hand and see the impacts on terrain parameters (such as slope and hydrology) in near real time. A laser scans the surface of a tangible model as the user manipulates it, and the Geographic Resource Analysis Support System (Grass) GIS processes the elevations. The impacts of these modifications to the surface on various terrain parameters are calculated and maps showing the results of any changes are projected back onto the physical surface. A flood control application illustrates how the interactivity of this system might aid in landscape redesign.
In combination, these articles demonstrate that research in cartography, GIS, and visualization is evidently continuing apace! Geovisualization is a discipline emerging from these fields and from the synergy between the use of cartographic principles in visualization and the development of maps that use visualization techniques. The articles presented here are indicative of several defining characteristics of geovisualization in that
• the activities that contribute toward geovisualization—such as using open formats and developing interactive online tools for demonstrating ideas—can help facilitate the cross-disciplinary communication and collaboration that is required;
• new cartographic possibilities for innovative, dynamic representations are developing as we take advantage of techniques from other disciplines and expand into multimodal, haptic, and multisensory interfaces to our geospatial data; and
• however technically sophisticated they become, our digital maps must be grounded in appropriate theory and evaluated through experimental frameworks that allow us to begin to comprehend the effects and utility of techniques that are evolving.
We hope you enjoy exploring the broad range of applications associated with geovisualization as you read this issue.
We acknowledge the thoughtful consideration of Associate Editors in Chief Maureen Stone, Holly Rushmeier, and Mike Potel, as well as Editor-in-Chief John Dill, who responded promptly to our many questions on procedures and reviews. This review process could not have been effectively completed if it were not for IEEE CG&A's society publications coordinator, Alkenia Winston.
is the director of the Center for Visualization and Analytics in the Department of Computer Science at North Carolina State University. In 1996, she founded the ACM Siggraph Carto Project that she continues to direct. In addition, she is also a member of the International Cartographic Association's Commission on Visualization and Virtual Reality. Rhyne is the editor of the Visualization Viewpoints department of IEEE Computer Graphics and Applications
and serves on the magazine's editorial board. She is a senior member of the IEEE and the IEEE Computer Society. Rhyne has the degree of Engineer (post-master's degree) in geotechnial—civil engineering from Stanford University. Contact her at firstname.lastname@example.org.
is the 2004–2007 E. Willard and Ruby S. Miller professor of geography and director of the GeoVISTA Center at Pennsylvania State University. He also directs the new North-East Regional Visualization & Analytics Center. MacEarchren's research interests include geovisualization, geocollaboration, interfaces to geospatial information technologies, human spatial cognition as it relates to use of those technologies, human-centered systems, and user-centered design. He served as chair of the International Cartographic Association Commission on Visualization and Virtual Environments and was named honorary fellow of that organization in 2005. He was also a member of the National Research Council Computer Science and Telecommunications Board Committee on the Intersections Between Geospatial Information and Information Technology and of the National Visualization and Analytics Center R&D Agenda panel. He is an IEEE Computer Society member. MacEachren has a PhD in geography from the University of Kansas. Contact him at email@example.com.
is a senior lecturer in geographic information at City University London with research interests in computer cartography and geovisualization. He has developed a number of software applications including cdv and panoraMap and published research papers on dynamic cartography. He sits on the editorial board of Computers, Environment and Urban Systems
. He is a member of the British Cartographic Society and the ICA Commission on Visualization and Virtual Environments. He is a National Teaching Fellow of the UK Higher Education Academy. Dykes has a PhD in geography from the University of Leicester. Contact him at firstname.lastname@example.org.