Elijah Meeks - D3.js in Action

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Ive always loved making games. Board games, role-playing games, computer gamesI just love abstracting things into rules, numbers, and categories. As a natural consequence, Ive always loved data visualization. Damage represented as a bar, spells represented with icons, territory broken down into hexes, treasure charted out in a variety of ways. But it wasnt until I started working with maps in grad school that I became aware of the immeasurable time and energy people have invested in understanding how to best represent data.

I started learning D3 after having worked with databases, map data, and network data in a number of different desktop packages, and also coding in Flash. So I was naturally excited when I was introduced to D3, a JavaScript library that deals not only with information visualization generally, but also with the very specific domains of geospatial data and network data. The fact that it lives in the DOM and follows web standards was a bonus, especially because Id been working with Flash, which wasnt known for that kind of thing.

Since then, Ive used D3 for everything, including the creation of UI elements that youd normally associate with jQuery. When I was approached by Manning to write this book, I thought it would be the perfect opportunity for me to look deeply at D3 and make sure I knew how every little piece of the library worked, while writing a book that didnt just introduce D3 but really dived into the different pieces of the library that I found so exciting, like mapping and networks, and tied them together.

As a result, the book ended up being much longer than I expected and covers everything from the basics of generating lines and areas to using most of the layouts that come to mind when you think of data visualization. It also devotes some space to maps, networks, mobile, and optimization.

In the end, I tried to give readers a broad approach to data visualization tools, whether that means maps or networks or pie charts.

Id like to thank my wife, Hajra, for giving me the support and inspiration and the keen editorial eye necessary for a book like this.

Id also like to thank Manning Publications for the chance to write this book. The exercise of writing a book like this serves as a finishing school for learning about a library, and as a result of writing D3.js in Action, I feel more confident with D3 than I would have had I simply created applications. Id like to especially thank my editor, Susanna Kline, for her patience and hard work at turning my prose into something worth buying. Also, thanks to the production team and everyone else at Manning who worked on the book behind the scenes.

The following reviewers provided feedback on the manuscript at various stages of its development, and I thank them for their time and effort: Prashanth Babu V V, Dwight Barry, Margriet Bruggeman, Nikander Bruggeman, Matthew Faulkner, Jim Frohnhofer, Ntino Krampis, Andrea Mostosi, Arun Noronha, Alvin Raj, Adam Tolley, and Stephen Wakely. Thanks also to technical editor Valentin Crettaz and technical proofreader Jon Borgman for lending their expertise and making this a much better book.

Finally, Id like to thank Stanford University Library and all the people there, but especially the head of that library, Mike Keller, for giving me the opportunity to use D3 to create amazing new research and applications in a number of exciting projects.

People come to data visualization, and D3 particularly, from three different areas. The first is traditional web development, where they assume D3 is a charting library or, less commonly, a mapping library. The second is more traditional software development, like Java, where D3 is part of the transition into HTML5 development. The last area is a trajectory that involves statistical analysis using R, Python, or desktop apps.

In each case, D3 represents two major transitions for folks: modern web development and data visualization. I touch on aspects of both that may give a reader more grounding in what I expect to be new and strange fields. Someone whos intimately familiar with JavaScript may find that some of these subjects (like function chaining) are already well understood, and others who know data visualization well may feel the same way about some of the general principles, like graphical primitives.

Although I do provide an introduction to D3, the focus of this book is on a more exhaustive explanation of key principles of the library. Whether youre just getting started with D3, or youre looking to develop more advanced skills, this book provides you with the tools you need to create whatever data visualization you can think of.

This book is split into three parts. The first three chapters focus on the fundamentals of D3. Youll see data-binding, loading data, and creating graphical elements from data in a variety of different ways. It also deals with scales, color, and other important aspects of data visualization that you might already know well. Some of the core technologies used by D3, like JavaScript, CSS, and SVG, are explained throughout these chapters.

The next five chapters use D3 in the ways we typically think of. is devoted to manipulating traditional HTML elements, like paragraphs and lists, to demonstrate that D3 is not tied to SVG.

The last three chapters and chapter 12 (online only) cover topics that can be considered deep diving into D3. Ive found that each has become an important part of my own practice. This includes principles for wiring up your own data dashboard, creating your own D3 layouts and components, optimizing data visualization for large datasets, and writing data visualization for mobile. Even if you dont think youll ever be using D3 in these ways, each of these chapters still touches on key aspects of using D3.