Visualizing Information Using SVG and X3D Vladimir Geroimenko and Chaomei Chen (Eds) Visualizing Information Using SVG and X3D XML-based Technologies for the XML-based Web With 125 Figures including 86 Colour Plates 123 Vladimir Geroimenko, DSc, PhD, MSc School of Computing, University of Plymouth, Plymouth PL4 8AA, UK Chaomei Chen, PhD, MSc, BSc College of Information Science and Technology, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104-2875, USA British Library Cataloguing in Publication Data Visualizing information using SVG and X3D:XML-based technologies for the XML-based web 1. Information visualization 2. computer graphics 3. SVG (Document markup language) 4. XML (Document markup language) 5. Semantic Web I. Geroimenko,Vladimir, 1955– II. Chen, Chaomei, 1960– 005.2′76 ISBN 1852337907 CIP data available Apart from any fair dealing for the purposes of research or private study, or criticism or review, as per- mitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the pub- lishers, or in the case of reprographic reproduction in accordance with the terms of licences issued by the Copyright Licensing Agency.Enquiries concerning reproduction outside those terms should be sent to the publishers. 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Typeset by Gray Publishing, Tunbridge Wells, UK 34/3830-543210 Printed on acid-free paper SPIN 10942703 Contents Foreword by Tony Parisi . vii Preface . ix Contributors . xiii Part 1: Using SVG and X3D in Generic Web Applications . 1 1 SVG and X3D in the Context of the XML Family and the Semantic Web. 3 Vladimir Geroimenko 2 The Foundations of SVG . 21 Kurt Cagle 3 X3D Fundamentals. 63 Don Brutzman, James Harney and Curt Blais 4 SVG as the Visual Interface to Web Services . 85 Shane Aulenback 5 X3D Graphics, Java and the Semantic Web. 99 James Harney, Alan Hudson, Curt Blais and Don Brutzman 6 Distributed User Interfaces: Toward SVG 1.2. 119 Kurt Cagle 7 Publishing Paradigms for X3D . 153 Nicholas F. Polys Part 2: Applying SVG and X3D to Specific Problems . 181 8 Visualizing Complex Networks . 183 Chaomei Chen and Natasha Lobo 9 Applying SVG to Visualization of Chemical Structures and Reactions. 202 John Leaver v vi Contents 10 Using Metadata-based SVG and X3D Graphics in Interactive TV . 225 Artur Lugmayr and Seppo Kalli 11 Knowledge Visualization Using Dynamic SVG Charts . 245 Nikolas A. Rathert 12 Using SVG and XSLT to Display Visually Geo-referenced XML . 256 Timothy Adams 13 Using Adobe Illustrator to Create Complex SVG Illustrations . 266 Sara Porter 14 X3D-Edit Authoring Tool for Extensible 3D (X3D) Graphics . 285 Don Brutzman 15 Concluding Remarks . 293 Vladimir Geroimenko and Chaomei Chen Index. 295 Foreword Correcting the Great Mistake People often mistake one thing for another. That’s human nature. However, one would expect the leaders in a particular field of endeavour to have superior abil- ities to discriminate among the developments within that field. That is why it is so perplexing that the technology elite – supposedly savvy folk such as software developers, marketers and businessmen – have continually mistaken Web-based graphics for something it is not. The first great graphics technology for the Web, VRML, has been mistaken for something else since its inception.Viewed variously as a game system, a format for architectural walkthroughs, a platform for multi-user chat and an augmentation of reality,VRML may qualify as the least understood invention in the history of infor- mation technology. Perhaps it is so because when VRML was originally introduced it was touted as a tool for putting the shopping malls of the world online, at once prosaic and horrifyingly mundane to those of us who were developing it. Perhaps those first two initials,“VR”, created expectations of sprawling, photorealistic fan- tasy landscapes for exploration and play across the Web.Or perhaps the magnitude of the invention was simply too great to be understood at the time by the many, ironically even by those spending the money to underwrite its development. Regardless of the reasons, VRML suffered in the mainstream as it was twisted to meet unintended ends and stretched far beyond its limitations. VRML was originally intended to be a platform for delivering, presenting and executing interactive 3D graphics – period, full stop. This meant any graphical application, ranging from the prosaic to the fictional, from fully photorealistic to purely synthetic. What attracted me to work on VRML in 1994 was its potential to transform the human–computer interface from a 2D window- and page-based metaphor into a 3D metaphor of objects and spaces.Such objects and spaces might be photorealistic and verisimilar; they might just as easily be abstract and fantas- tic. The point is: they are intended to convey information. The great mistake of Web media is that the developers and marketing machines of high-tech companies believe and actively promote the idea that the primary use for graphics is as “art rather than information”: the stuff of banner ads, games, walkthroughs and avatars. This misguided notion ignores the reality that comput- ers are still largely used for managing, sharing and communicating textual and numeric data. Take a look at today’s 2D computer applications. How many of them are oriented toward managing abstract entities – numbers, words or folders full of files – versus real-world images and sounds? You will discover that an overwhelm- ing majority of these applications are intended for the former. Granted, images, sounds and video account for a growing amount of the data stored on personal vii viii Foreword computers and shared over the Web. However, even that data is presented via an organizing principle known as the user interface: an abstract thing,generated from underlying relationships in the data – not painted by artists. The Web is a fine place for sharing family photo albums, displaying ads and playing games. However, I predict that these applications of Web graphics will be dwarfed in comparison by its absorption into the mainstream in the form of sim- pler and more intuitive interfaces, rich media presentations, interactive training manuals and animated multidimensional charts. Ultimately, the percentage of 2D and 3D Web graphics created by artists compared with that generated using data visualization techniques will probably be close to the percentage of PC users who own a licensed copy of Photoshop, and the mix of applications roughly what we see on today’s desktop computers.As in the real world, art will constitute a minority of the use of the Web. This book is for those of us who wish to take advantage of the rich palette of objects provided by SVG and X3D – two new standards for delivering interactive 2D and 3D graphics and animations over the Web – but have neither the requisite skills nor the luxury of time to create original artwork and hand-crafted objects. We have data; we want to see and understand it. Visualizing Information Using SVG and X3D presents a range of techniques and tools for realizing that desire in code and in context. System programmers can use the information in this book to develop complex client–server frameworks for presenting and navigating data using rich media interfaces; application writers can integrate the results of that work to convey meaning for particular kinds of datasets; developers of authoring environments can provide drag-and-drop tools for creating easy to navigate user interfaces at the touch of a button. Together, these building blocks enable us to understand and interpret our information better and instantly share the results with everyone on the Internet. SVG and X3D are based on XML, the common glue that binds together the next generation of Web data. XML promises to be the foundation of a “Semantic Web”: a web where information is given meaning.Although art will play an important role in the unfolding of this new Web, that role will not be fundamental. The Semantic Web will be built upon data,reified in graphics and sounds generated by programs. The software developers and information designers working in data visualization today are the architects of a new and brilliant medium for understanding our world. This book provides an entry point for joining that revolution. It also repre- sents a vital course correction for Web graphics: maybe now we can stop chasing the butterflies and get back to changing the world. Tony Parisi San Francisco, California 18 May 2004 Preface Vladimir Geroimenko and Chaomei Chen Information visualization is one of the most important and well-established areas of research and development. In recent decades, it experienced remarkable achievements, especially in enhancing the visual appearance of the Web in order to make it more attractive and useful for the user. As has happened with many other areas, the Web has become one of the few ubiquitous driving forces behind the cur- rent development of information visualization. The Web is undergoing revolutionary changes – its second generation is emerg- ing. The key player in the new generation is not HTML but XML (this is why it is also known as “the XML-based Web”).