Introduction
When it comes to the web, you may have heard the expression “Content is king.” Coined by Bill Gates in the 1990s, this oft-repeated mantra stresses the importance of information above all else. Think about it: The average user doesn't visit your site to admire a beautiful design or cool animation—she goes there for content. In that sense, everything we do as web professionals—whether it's design, development, or marketing—has a single goal: conveying information to the user.
And what better source of information is there than raw data? That said, raw data by itself is nothing more than static noise. Data visualization allows us to bridge that gap, turning raw data into meaningful content.
At this point, you've probably gathered that data visualization is a lot more than flashy widgets to impress your boss. Although this book does cover some impressive tools—such as the comprehensive D3 library—the focus at all points is on the information. At a minimum, data visualization conveys this information to the user. But you're going to go deeper than that. That's because data visualization is capable of so much more; in addition to conveying information, data visualization analyzes information to provide meaningful insights.
Good data visualization doesn't just aggregate data into more digestible chunks. Good data visualization leads users to powerful conclusions. It shows rather than tells, and in our experience there is no better way to get your point across. There's just no substitute for leading users to a conclusion they can then draw for themselves.
What's in This Book
JavaScript and jQuery for Data Analysis and Visualization starts off in Part I with a broad discussion of data visualization. It discusses the current state of data visualization and its general goals, and then it covers some of the basic tenets of analysis. Part I closes with an overview of some of the technical foundation that you need to understand the rest of the book, such as the basics of HTML5 canvas and SVG.
Part II takes you into the realm of data analysis and acquisition. It discusses techniques for pulling data from a server and even covers how to combine stored data with form data from the user. Next, it covers data validation as well as techniques for displaying tabular data. Part II wraps up with a discussion of client-side analysis tools, providing a robust statistical analysis toolkit that's based in JavaScript.
Part III explores actual data visualization tools, and in all likelihood it's going to be your favorite part of this book. You'll start off by running through basic charting solutions such as Google Charts. From that point, the book gets into more complex charting options—covering how to build custom solutions with Raphaël as well as how to use the D3 library. Finally, you learn all about more specific data-visualization applications, such as geographic and stock data.
Last but not least, Part IV consolidates everything you learned in Parts I through III with a couple of real-world examples. You first see how to build an interconnected dashboard that renders U.S. Census data using Google Charts and then you see how to use D3 in production to create reusable visualizations.
Who This Book Is For
This book is geared toward web developers with a basic understanding of front-end development. Although you don't need to have advanced skills in this realm, you should have at least a beginner's level of knowledge of JavaScript and jQuery. Beyond that, we make no assumptions of your skill level. We cover data visualization tools from the ground up, as well as some of their underlying technologies. Whenever possible, we point you to external resources to further support your knowledge in these areas. That way, we can cover the basics quickly and move on to the more and impressive parts of data visualization.
By the end of the book, you'll have advanced knowledge of a variety of data visualization tools and techniques. This book will provide you with a comprehensive toolkit to handle all your visualization needs.
Conventions
To help you get the most from the text and keep track of what's happening, a number of conventions are used throughout the book.
As for styles in the text:
We highlight new terms and important words when we introduce them.
We show filenames, URLs, and code within the text like so: persistence.properties.
We present code in two different ways:
We use a monofont type with no highlighting for most code examples.
We use bold to emphasize code that's particularly important in the present context or to show changes from a previous code snippet.Companion Website
To complement the content in this book, we've also created a companion website at www.wrox.com/go/javascriptandjqueryanalysis. This website provides a variety of useful resources, such as downloads of all the code examples in the book. It's a useful place to turn if you get stuck at any point.
Errata
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If you don't spot “your” error on the Book Errata page, go to www.wrox.com/contact/techsupport.shtml and complete the form there to send us the error you have found. We'll check the information and, if appropriate, post a message to the book's errata page and fix the problem in subsequent editions of the book.
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