Article for the GIS@development professional magazineInternet GIS: today’s realities and a vision of the future Ming-Hsiang Tsou Email: [email protected] Internet GIS is a very hot topic today. It has a tremendous potential in almost every subfield of traditional Geographic Information Systems (GIS). It may even change our life style in the next few years. Huge outlays of effort, money, and people have developed the related technologies, software packages and applications. Most GIS professionals expect that the Internet is the futureof GIS. This paper provides an introduction to Internet GIS technologies by discussing today’s realities and a vision of the future Internet GIS. This paper will also introduce some examples ofdata standards for the Internet GIS in the United States. What is Internet GIS? What is Internet GIS? The book, Internet GIS: distributed geographic information services for the Internet and wireless networks, defines Internet GIS as “network-based geographic information services that utilize both wired and wireless Internet to access geographic information, spatial analytical tools, and GIS web services.” (Peng and Tsou, 2003, p. xxx). There are a few key concepts in this definition. First, “network-based” indicates that the whole framework of Internet GIS is sharable and exchangeable. Second, the method of telecommunication includes both “wired and wireless”. Mobile devices (like PDAs, cellular phones, and Pocket PCs) with wireless communication are an integral part of the Internet GIS framework. Finally, the contents of Internet GIS include not only displaying Internet maps or sharing on-line geospatial information, but also providing advanced GIS analysis functions and new information services. Examples include virtual touring, children location-monitoring, social services, and others. The distributed Internet GIS framework, is an example of the revolution of information systems -- from traditional architecturally closed and centralized information systems to more open and distributed information service architectures (Tsou and Buttenfield, 2002). The driving force behind this transformation of GIS architecture is the availability of new technology in network communication and programming. New languages such as Java, Python, and C# (C-sharp) support platform-independent applications across the Internet. Advanced network technologies, such as Microsoft .NET framework, J2EE platform, and Common Object Request Broker Architecture (CORBA) provide a comprehensive scheme for distributed component technology essential to the development of Internet GIS. Distributed component technology allows clients to access heterogeneous servers dynamically, which is an essential feature of distributed GIServices. We foresee a future in which traditional GISystems, designed as isolated islands, will become increasingly less attractive, maybe disappearing altogether. The cost efficiencies and flexibility of reusable and interoperable open and distributed services interfaces will provide greater economies. GIServices focus on open, distributed, task-centered services, which will broaden geographic information uses into an increasingly wide range of on-line geospatial 1applications These include digital libraries, digital governments, on-line mapping, data clearinghouses, real-time spatial decision support tools, distance learning modules, and so on. Three kinds of Internet GISInternet GIS has many difference faces and alternative names, such as “internet mapping”, “distributed GIS”, “web-based GIS”, “networked GIS”, “on-line GIS”, etc. To simplify the variety of Internet GIS, we identify three kinds of Internet GIS: Internet GIS for data sharing, Internet GIS for information sharing, and Internet GIS for knowledge sharing (Figure 1).Figure 1. Three kinds of Internet GIS.The first type of Internet GIS is for data sharing. Data sharing combines with the functions of on-line data archive and data search services. Two typical applications are on-line data warehouses (or data archive centers) and on-line data clearinghouse. An on-line data warehouse is for archiving, accessing and downloading both GIS databases and/or remotely sensed imagery.For example, the USGS National Map Seamless Data Distribution System is an example of an on-line GIS data discovery service (http://seamless.usgs.gov/). A web-based data clearinghouse can help users to search and index the contents of metadata, and then access the actual data through the descriptions of metadata. Clearinghouses may access dataset or inventory detail. The premier dataset clearinghouse portal for Federally acquired data is the Federal Geographic Data Committee (FGDC)’s data clearinghouse ( http://clearinghouse3.fgdc.gov/ ). Clients can access descriptions of datasets, and may be redirected to the dataset holder to access individual dataset granules. NASA’s Earth Science Data Information System (ESDIS) Project’s new ECHO system is an example of an inventory clearinghouse. Clients of an inventory clearinghouse can access descriptions of individual dataset granules and can broker data orders to providers on behalf of users (Pfister et. al., 2001).ApplicationsOn-line data warehouses (data archive)On-line data clearinghouse (metadata)Data SharingInformation SharingKnowledge SharingThree Kinds of Internet GISApplicationsWeb-based map display Navigation ServicesApplicationsOn-line GIS modelsWeb-based spatial analysis tools2The second type is for information sharing. Multiple interactive map servers and mobile navigation services are the typical applications. Web-based mapping functions include the display, zoom-in/out, query of spatial information. The major requirement of information sharing services is to provide effective web-based display mechanisms and client/server communication protocols (Tsou, 2004). One on-line mapping example can be found at the U.S. Census Bureau American Factfinder (http://factfinder.census.gov/servlet/ReferenceMapFramesetServlet?_lang=en). The reference and thematic maps provided by the Factfinder are built on the OGC standards and use data represented in the Geography Markup Language (GML) standard. The third kind of Internet GIS focuses on the sharing of knowledge. This is the most challengingtask for the development of Internet GIS and only few applications available today. The goal is to provide on-line GIS modeling and