Getting Started with D3

Chapter 1. Introduction

Visualizing data is now an old trade. We have, in one way or another, been visualizing collected data for a long time—the year of this writing is the 143rd birthday of Minard’s famous Napoleon’s March flow map shown in Figure 1-1. Lately, though, we’ve gone into overdrive, as the amount of data we capture increases without bound and our ability to glean insights from it develops and matures. The Internet, combined with the latest generation of browsers, gives us a fantastic opportunity to take our urge to visualize to the next level: to create live, interactive graphics that have the opportunity to reach millions of people.

Figure 1-1. Minard’s flow map depicting Napoleon’s dwindling army as he marches toward, and retreats from, Moscow. “Drawn up by M. Minard, Inspector General of Bridges and Roads in retirement. Paris, November 20, 1869.”

JavaScript is the language of the modern browser. As such, it is the most installed language in the world: the one language you can be confident is installed on the user’s computer. Similarly, all modern browsers (with the introduction of IE9 in 2011) can render Scalable Vector Graphics (SVG), including mobile devices that are unable to render Flash. Together, the combination of JavaScript and SVG allows us to create sophisticated charts that are accessible by a majority of Internet users. And, thanks to D3, bringing these ...