Technologies for Delivering Geospatial Information on the Internet

Internet Information Standards
This section describes some of the key data formats and languages used to send and store information on the Internet. The particular focus is on formats and languages that can be used to describe geospatial information.

Extensible Markup Language (XML)

What is XML?
Deregulation, restructuring, and the introduction of e-Business to traditional business marketplaces is causing industry to become keenly aware of the need to exchange data as effectively, efficiently and inexpensively as possible. This need applies to spatial data just as much as more traditional forms of business information, particularly if we would like to see geospatial information to jump out of the back-office in which it is so often isolated. XML is a relatively recent innovation that many herald as the best way to meet the electronic data transfer and storage needs of business in the Internet age. XML has emerged as a key format on the Web, particularly for Business-to-Business integration. With the widespread development of XML variants for specific B2B markets, and the improved flexibility and adaptability it offers, XML will soon replace EDI (Electronic Data Interchange) as the standard format for exchanging digital information between companies. XML also forms the basis for several geospatial data languages discussed later in this paper.

XML is a universal, text-based data exchange standard. In traditional data exchange formats, such as EDI, data is defined by the position it takes in the file structure. In XML the position of the data is not important – instead, tags identify or define the data content. This is in contrast to HTML, which uses tags to describe how a document should be displayed. For example, XML tags specify that a piece of text 'is a price' or 'is a date', while HTML tags specify that a piece of text 'is bold' or 'is a heading'. XML carries the identification of each data element along with the data itself. Goals of XML:

easy to use
broadly applicable
unambiguous
international
platform-independent

In the future, more and more applications will speak XML natively “out of the box”, especially as standards solidify. “Plug-and-play” B2B exchange standards (like RosettaNet in the computer industry) can have tremendous impacts on operational efficiency and costs by automating the exchange of information from back to front office throughout a supply chain. They can also provide more competition (and lower prices) by opening up marketplaces to smaller, more nimble participants, and increase revenue opportunities by providing more information, in a more timely, efficient manner, to potential customers.

Why XML?
Most large enterprises expend significant portions of their IT budget on developing methods to transfer information between isolated systems. XML helps to solve this problem by providing a flexible, platform-independent way of transferring data over standard network protocols. Data that is being transferred between systems can be easily translated to and from a standard XML format. By providing a well-known, easy to use intermediary format, XML helps avoid the need for constantly linking different systems to each other in 'point-to-point' solutions. XML has emerged as the key technology in so-called Enterprise Application Integration (EAI) - used to link together traditionally isolated information systems, both within a single enterprise, and across an extended e-Business on the Internet.

According to the Utility Industry Group (UIG):
“XML holds a great deal of promise for all aspects of the utility industry. Our recommendation is that the UIG proceed with XML message standards by developing the schemas and data models necessary to implement electronic business transactions for the utility industry.” XML is license-free and vendor/platform-independent. It is supported by a growing number of individuals and organizations. There are an increasing number of tools (many are free) for editing, generating, viewing, and transforming XML. XML provides a flexible, extensible mechanism that can handle any type of information. Currently, numerous standard languages based on XML are being developed for specific industries or applications (some of these are described later in this paper).