Internet GIS

Internet GIS refers to the use of the Internet as a means to exchange geospatial data, perform geographic information system (GIS) analysis, and visualize maps. Like many other new research fields, there is no general agreement on the term Internet GIS. Several alternative names have been adopted in the GIS community to represent similar concepts, such as online GIS, distributed geographic information (DGI), and Web-based GIS (or Web GIS). These different terms are similar, but they are not synonymous. For example, Web-based GIS refers to the use of Web browsers as the primary viewers/containers to conduct GIS tasks. However, some popular GIS applications, such as Google Earth, use their own browsers instead of relying on the default Web browsers. Therefore, Google Earth is an Internet GIS application, but it is not a Web-based GIS application. The term Internet GIS has a broader and more enduring meaning than Web-based GIS. It has the capacity to include other and new applications of GIS and the Internet.

The Internet is a modern information relay system that connects hundreds of thousands of telecommunication networks and creates an “internetworking” framework. The Internet framework includes local area networks (LAN), wide area networks (WAN), Internet Service Provider (ISP) networks, wireless communication networks, and intranets. Intranets are a subset of the Internet that use the same Internet Protocol and communication technologies within a closed environment, such as a company network, but with limited access and security enhancement.

Early Internet GIS prototypes appeared in the mid 1990s. Xerox Map Viewers, the Alexandria Digital Library project, and GRASSLinks are a few representative Internet GIS prototypes from [Page 1621]the early period. More recently, we have witnessed an explosion of interest in transforming GIS into the ubiquitous, distributed Internet GIS. These services are of value not only to various professionals using geospatial data in their daily work but also to the general public, to use spatial information for navigational and other purposes involving location-based data. There are Web sites powered by Internet GIS that allow people to check city zoning and parcel information, see where and what types of crimes are occurring in their neighborhoods, and learn when is the trash pickup day on their street.

Figure 1 The three-tier architecture of the Internet GIS

Source: Author.

GIS on the Internet presents a compelling and effective way of disseminating spatial information when compared with traditional paper maps or digital maps stored in centralized GIS or on CDs. Though the melding of GIS and the Internet seems a commonplace now, the idea was revolutionary in 1993. One of the earliest Internet GIS prototypes, called Xerox PARC Map Viewer, appeared on the World Wide Web that year. Developed at Xerox Corporation's Palo Alto Research Center, the Map Viewer allowed users to zoom in on a location on a picture-based map rendering of a globe and retrieve a map of the selected area from a geographic database. In 1994, two important organizations promoting standardization in Internet GIS were established: the Open Geospatial Consortium (OGC) and the International Organization for Standardization (ISO) Technical Committee 211 (TC211). Specifications developed by OGC and ISO/TC211 for spatial data formats, data exchange, and data communication have become the basis for software interoperability and the ongoing development of Internet GIS. Along with the rapid development of Internet GIS, a new term, geospatial cyberinfrastructure, is used to represent the combination of distributed high-performance geospatial computing resources, georeferenced information, geoprocessing Web services, and geographic knowledge.

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