Abstract
In this chapter the authors explore the contribution visualization can make to the new interfaces of the Semantic Web in terms of the quality of presentation of content. In doing this they discuss some of the underlying technologies enabling the Web and the social forces that are driving the further development of user-manipulable interfaces.
TopWhat Is Visualization?
The History of Visualization
There is no accepted definition of visualization but it can be adequately summarized for our purposes as using visual means to aid the communication and understanding of information. Modern visualization increasingly uses computer graphics technology to make information accessible. Visualization’s long history predates the origin of computers by at least 8 thousand years. Maps are one of the oldest forms of graphical aid whose continued usefulness is demonstrated by the fact that mapping applications are amongst the most popular web-based applications. Before computers visualizations generally were not interactive, though there are exceptions to this as some scientists developed models and pop ups in books to explain their ideas but these were rare and expensive (Tufte, 1997; Tufte, 2001).
The roots of visualization are tangled into our history; a timeline of visualization is available on the internet (Friendly, 2008). Many historical breakthroughs were made possible through visualization, such as John Snow’s use (in London in 1854), of maps to show the distribution of deaths from cholera in relation to the location of public water pumps. Visualization has never been an isolated discipline; it has been an integral element of scientific, intellectual and technical developments.
The timeline of visualization shows that the development of visualization has accelerated since 1975, since when important changes have depended upon advances in computing. Improved computer speed and capacity increasingly allow data to be visualized by increasingly intensive computational methods. Computers make visualizations more interactive and allow direct manipulation of data, e.g. selecting data by linking, brushing or using animation in grand tours. Also driving the development of visualization is the fact that visualization methods are being applied to and developed for an ever-expanding array of problem areas and data structures, including web applications that enable social networking.
Key Terms in this Chapter
Google Earth: The most popular visualization tool ever. It is a standalone web application combining maps, satellite and GIS information into a meaningful spatial context that gives the user direct manipulation of the applications elements.
Visualization: There are many definitions of visualization. In this chapter we use the term to cover the use of computer and computer graphics technology to present data to aid human understanding and communication. Today visualization is somewhat arbitrarily divided into scientific and information visualization.
VRML: is a file format that holds 3D models. Some animation and interactivity is encoded into the file.
Scientific Visualization: The first distinct area of visualization to have developed. Initially computer graphics technology was used to “view” the result of computer simulations which had an inherent geometry e.g., the flow of air over an aircraft.
Java: A powerful programming language that adds functionality to the web at the server side and the client (browser) side. Several libraries relevant to visualization are included within Java.
API: (Application Program Interface) contains all the elements that a programmer needs to extend an application.
CMS: (Content Management System) a web delivery system separating content from presentation. These allow users to add content making them popular in social networking sites but the web pages have a tabular form that isolates the elements that make up the content.
Information Visualization: The final area of visualization to emerge that aimed to show visually the relationships within databases.
Flash: is a multimedia web application adding animation and interactivity to web pages by using efficient streaming and vector graphics techniques.
Data Visualization: The second area of visualization to emerge that focused on statistical plots and thematic cartography has now merged with information visualization.
JavaScript: A scripting language that adds interactivity into web pages.