Foreword: Special Issue: Web and Wireless Geospatial Information Systems
Geospatial information technologies including precise navigation and positioning, remote sensing, and geospatial information systems (GIS) are increasingly employed as effective tools for environmental monitoring and resource management worldwide. Over the past decade, we have witnessed the increased mounting of these tools onto the Internet or the World Wide Web (Web). Indeed, Web has been becoming a portal for GIS and image analysis functionalities as well as data distribution. Also, we have seen the shifting of Web GIS from simple mapping to more complex spatial analysis, real-time collaboration, and incorporation of specialized models and decision support. Despite the progress and its increasing integration with wireless networks, significant challenges still exist. This special issue reflects, from a unique perspective, some current research and application endeavors involved in web and wireless GIS.
Web GIS allows for interoperability which in turn enables the integration of data between organizations and across applications and industries, resulting in the generation and sharing of more useful information. One important technology related to this contribution is spatial web portal (SWP). The SWP, like GOS (Geospatial One-Stop, http://www.geodata.gov), is now an indispensable part of e-government and information infrastructure. By maintaining a repository of metadata about the geospatial information or services and links to other catalog services, clearinghouses and the more, the SWP integrates different distributed geospatial data sources, offering easier locating and access target geographic data needed and manned or automatically data submission\harvesting from government agencies, and so forth. Likewise, such catalog service is also employed by grid service to facilitate geo-scientific collaboration. Geospatial Knowledge Grid proposed by researchers at George Mason University in USA, for instance, combines OGC (the Open Geospatial Consortium) and Grid technology, designed a standard compliant Grid Enable catalogue service for Web (GCS/W) to make NASA’s Earth Observing System Data and Information System (EOSDIS) data easily accessible to Earth science communities.
One disadvantage with catalog service is that, sometimes, building up or supplementing a metadata catalog is onerous. Usually, people incline to directly access to heterogeneous data sources, thus saving the burden to establish a uniform interface--portal from scratch. In this case, a client has to face to numerous data servers, each of them may have distinct data model, which not only diversified in schema, but also in semantic sense, like ambiguous meanings underlie different datasets. This issue so far has generated many solutions, like Z39.50, geospatial pattern match of different classes, and so on, among which using geo-ontology to represent a domain’s knowledge increasingly gains widely acceptance. Even so, information retrieval among heterogeneous data sources still continues to be a challenging task.
Collecting geospatial data is only a preliminary step rather than a final solution for web GIS. Traditionally, web GIS has often been critized for its limited analysis functions either to public or to specialists. Better support for analysis, modeling and decision support within web GIS is needed in order to move users beyond the “data-to-data” mode towards “data-to-models” and “data-to-interpretation” mode. In pace with the Web 2.0, the representation of real geographical environment shifts from static 2D to dynamic 2D and 3D, thanks to global grid data model and virtual reality technology, therefore enabling more users involved in the buildup process of web/Internet GIS, like Google Earth, ArcGIS Explorer. These improvements also profoundly enhance the web-based public participation GIS (PPGIS) in urban planning, ecological sustainability aspects, allowing common person partake in the decision making process of the issues related to their common life. The paper by Li, S. et al. presents a new approach to GIS-enabled virtual public meeting space for public participation. The work carried out by Wagtendonk and De Jeu evaluates the use of mobile GIS for an archaeological case study and demonstrates benefits of applying specific mobile computing methods in scientific fieldwork. Information retrieval and intelligent search among heterogeneous data sources has always been a hot topic in the GIS community. The paper by Yi et al. presents methods that use the semantic information of context of geodata source and employ attributed relational graph and probabilistic relaxation for pattern matching among heterogeneous geodata sources. Previous research and industrial applications have confirmed the effectiveness of geospatial catalogue in facilitating the discovery and sharing of massive amounts of geospatial data. As these geospatial catalogues are rapidly becoming online catalogue services, there comes a need to build a federation to fulfill distributed and integrated metadata discovery. The study presented by Bai et al. addresses the application of a Catalogue Federation Service that integrates three online geospatial catalogue services and the successful application of this federation in the NASA GeoBrain project shows the feasibility and applicability of their proposed design. A study on spatial web portal made by Yang et al. describes NASA’s Earth Science Gateway (ESG), which has adopted their architecture to share Earth observations, simulations, and other research results to support decision-making applications. As for specialized domains of web GIS, with more specialized spatial analysis methods added in, specific applications are broaden as well. Newly influential examples includes: web-based geological hazard monitoring in the Three Gorges area of China (Niu et al.), network-based infrastructure interdependency modeling (Abdalla et al.), and web GIS for the Mars Exploration Rovers (MER) 2003 Mission (Li, R. et al.). However, there is still much space for extending existing research challenges, especially in the spatial analysis, decision support aspects.
Web GIS is now also well-integrated with mobile GIS to support mobile applications, such as facilitating scientific field work and providing location based services. The mobile application is a modified version of web application to work within the compute environment of portable equipment, like personal digital assistants (PDAs). Take location-based services (LBS) for instance, examples of such applications include location-aware emergency service, location-based advertisement, live traffic reports, and location-based information delivery service. For the field work, if the mobile device would have a local wireless (e.g., Bluetooth) connection, rapid analysis in the filed for non-collection studies would be possible. Spatial statistics in the field would also allow users to explore digital spatial data in real-time and improve their methodology in an iterative manner. Further work for the use of mobile GIS methods in scientific fieldwork planned on the improvement of field communication and data-exchange possibility for guidance and feedback from specialists at the office.
The eight papers included in this special issue represent the recent efforts of many of the researchers who have been involved in the development of web and wireless GIS technologies over the past decade. The initial response to the call for papers for this special issue was somewhat overwhelming. After careful consideration and consultation with many individuals, the present sequence of papers was deemed to be representative of the state-of-the-art. Many people and organizations have contributed in innumerable ways to the development and success of web and wireless GIS technology as it is found today. Special thanks go to the following individuals who were gracious enough to donate their time during the review process of this special issue: Thierry Badard, Michela Bertolotto, James D. Carswell, Volker Coors, Tom Cova, Urska Demsar, Cherie Ding, Georg Gartner, Andrea G. Fabbri, Daniel Holweg, Hassan Karimi, Tom Kralidis, Jiyeong Lee, Ki-Joune Li, Darka Mioc, Ziqiang Ou, Wolfgang Reinhardt, Claus Rinner, Weibel Robert, Mike Sawada, Ming-Hsiang Tsou, Bert Veenendaal, Monica Wachowicz, Demin Xiong , Yong Xue, Xiaobai Yao, and Sisi Zlatanova.
Special Issue Editors
Dr. Jonathan Li
Associate Professor
University of Waterloo, Canada
Dr. Bo Huang
Associate Professor
The Chinese University of Hong Kong, China