Other Applications of SGML

SGML is now being widely adopted in the commercial world as companies see the advantage of investment in data that will move easily from one computer system to another. It is worth noting that the few books on SGML that appeared early in its life were intended for an academic audience. More recent books are intended for a commercial audience and emphasize the cost savings involved in SGML as well as the technical requirements. This is not to say that these books are not of any value to academic users. The SGML Web pages list many projects in the areas of health, legal documents, electronic journals, rail and air transport, semiconductors, the U.S. Internal Revenue Service, and more. SGML is extremely useful

for technical documentation, as can be evidenced by the list of customers on the Web page of one of the major SGML software companies, INSO/EBT. This list includes United Airlines, Novell, British Telecom, AT&T, Shell, Boeing, Nissan, and Volvo.

SGML need not be used only with textual data. It can be used to describe almost anything. SGML should not therefore be seen as an alternative to Acrobat, PostScript, or other document formats but as a way of describing and linking together documents in these and other formats, forming the "underground tunnels" that make the documents work for users.^[11] SGML can be used to encode the searchable textual information that must accompany images or other formats in order to make them useful. With SGML, the searchable elements can be defined to fit the data exactly and can be used by different systems. This encoding is in contrast with storing image data in some proprietary database system, which is common practice. We can imagine a future situation in which a scholar wants to examine the digital image of a manuscript and also have available a searchable text. He or she may well find something of interest on the image and want to go to occurrences of the same feature elsewhere within the text. In order to do this, the encoded version of the text must know what that feature of interest is and where it occurs on the digital image. Knowing which page it is on is not enough. The exact position on the page must be encoded. This information can be represented in SGML, which thus provides the sophisticated kind of linking needed for scholarly applications. SGML structures can also point to places within a recording of speech or other sound and can be used to link the sound to a transcription of the conversation, again enabling the sound and text to be studied together. Other programs exist that can perform these functions, but the problem with all of them is that they use a proprietary data format that cannot be used for any other purpose.