Visualization of Metadata
Donald Beagle · Information Technology and Libraries · 1999
Visualization research has transformed the operating system environment of Web browsers and OPACs, but has not yet changed the way we manipulate content. The potential for visualization of metadata and metadata-based surrogates is discussed, including a command interface for metadata viewing, site mapping and data aggregation tools, dynamic derivation of surrogates, and a reintroduction of transient hypergraphs from the tradition of cocitation networking. Digital library research into query-specific instantiation through agents accessing a central metadata repository is also discussed in the context of potential synergies between querying, browsing, and group information sharing. A new generation of Web-based OPACs is now reaching the library marketplace, at the same time that libraries are experimenting with the inclusion of URLs and related surrogates for an expanded range of electronic information resources.(1) These OPACs make use of the graphical user interface (GUI) standards that originated with Xerox PARC and entered the marketplace through the Apple Macintosh Operating System (OS), Microsoft Windows, and Web browsers from MOSAIC to Netscape. But while GUIs generate a visual representation of the operating system environment, they remain primarily list-based on the level of record retrieval and access for both print and electronic resources. The user can interact with such lists to view very basic permutations, such as by date of creation or last modification, by application, by file name or type, and so on. This situation repeats itself with typical Web search engines. The user interacts with the search engines via the graphical environment of the browser, but is answered by search results in the form of hundreds or thousands of items in multipage sequential lists. GUIs displaced older interfaces such as MS-DOS by offering a better way to visualize the OS environment through a symbolic syntax of nouns (icons representing files and applications) and action verbs (pointers and menu commands). Over the past decade, a parallel line of visualization research has emerged from Xerox PARC and its brethren into the display of intrinsic or extrinsic relationships among various containers of content and their contextual domains of discourse. Whereas a GUI gives the user a graphical representation of an environment and toolset designed for the retrieval of information, knowledge visualization tools generate graphical representations of meaningful relationships among retrieved files or objects themselves. The potential benefits of such research may be suggested by the example of a typical city map. One side normally features an alphabetical list of street names paired with location codes. The other side features a grid aligned to the location codes showing icons representing streets, buildings, or sites of special interest. Each side of the map is a useful starting point for certain types of queries. The list side excels when the user knows the name of a street and formulates a quick directed search. But this fails to help the user who wishes to gain a general or in-depth overview of the relationships between commercial districts, residential neighborhoods, and recreational facilities. To extend the analogy: list-generating search engines and OPACs are useful to those entering the Web to retrieve specific predetermined chunks of information, but less useful to those who need an overview of Web resources related both to one another and to given domains of discourse. The GUI browser environment certainly offers the potential for integration of content visualization as well as a navigational schema equivalent to the map's coded locator grid, but there is still a dearth of applications offering graphical overviews of content. From the user's perspective, one side of the potential knowledge map remains perpetually blank. This is surprising, considering that browsers are designed for visually oriented browsing, as the nomenclature implies (i. …