Y. Leclerc, M. Reddy, L. Iverson, and A. Heller (2001). “The GeoWeb — A New Paradigm for Finding Data on the Web”. In Proceedings of the International Cartographic Conference (ICC2001), Beijing, 6-10 August 2001.
The Web has revolutionized the way documents are published, found, and viewed. This revolution has succeeded in part because Web protocols and publishing standards are open, and there exist freely available tools for publishing and reading Web documents. Just as importantly, powerful search engines let users find documents of interest almost instantaneously. Without these search engines, the Web would be almost useless.
Even though search engines can now find almost all Web-accessible documents about a given topic, it is currently impossible to find almost all web-accessible data about a given location. (Examples of such georeferenced data include aerial and satellite images, 3D models of buildings and weather systems, and vacation pictures taken with GPS-enabled cameras.) That’s because the location that the data refers to is typically not a part of the data itself. Thus, today’s search engine technology is not applicable and the huge amount of georeferenced digital data that is available on the Web today is virtually inaccessible.
In an attempt to make georeferenced data accessible, a number of companies and organizations have created private or governmental databases that hold a small fraction of all georeferenced data. Companies like Mapquest maintain private map databases with associated street addresses and links to businesses like restaurants and shops. Organizations like the Federal Geographic Data Committee (FGDC) maintain databases with government-owned imagery and feature data. These databases hold searchable metadata, a summary description of the data that includes geographic location, which can either be searched directly, or via a clearinghouse. However, none of these organizations is either capable of, or willing to, create a database that would allow anybody in the world to publish and search georeferenced metadata. Indeed, this task is so large that no single, regional, organization could do it alone.
What is needed instead is a coordinated global infrastructure with participating organizations from around the world. We call this infrastructure the GeoWeb. We propose to build and maintain this open standards-based infrastructure on a new top-level domain called .geo that will enable anybody to publish and search for all metadata referring to a given area. The infrastructure is based on a hierarchy of servers whose domain names represent geographic areas. An example hierarchy, described below, is nominally of the form minutes.degrees.tendegrees.geo. (For convenience, we use “.geo” as the top-level domain name in all of our examples of the GeoWeb hierarchy.)
Using the GeoWeb hierarchy, Web sites or specialized applications will let users specify a search profile (keywords and other pertinent information) and find all georeferenced data satisfying the profile in a given area. Because the data is georeferenced it can be embedded in 2D maps or 3D models of the Earth, letting the users navigate through the map or model, providing a much more natural means of finding data than traditional search engines.
In the remainder of this paper, we will describe the GeoWeb hierarchy and metadata, and some client applications.