Preface

Data is everywhere around us, and each day more of it is made available freely as open data or is published as a result of big data analytics. Although the data in itself is already really valuable, it is usually very difficult to present this data in a clear and concise way to a larger audience. D3.js gives us a way to easily represent this data and create standard-based, interactive data-driven visualizations, which can run on all devices, from phone to desktop. In this book, we'll explore all the different visualizations options provided by the D3.js APIs and show how you can use common patterns to create beautiful interactive visualizations using a minimal amount of coding. We'll also explore how you can prepare the data so that it can be easily visualized.

What this book covers

Chapter 1, Getting Started with D3, shows you how to get the code for this book and set up your development environment. We'll also explain the basic concepts behind D3.js and create our very first visualizations.

Chapter 2, Basic Charts and Shapes, explains how you can use the D3.js APIs to create basic shapes and charts. We'll show you how to create interactive line charts and animate pie charts.

Chapter 3, Working with Hierarchical Data, shows which APIs D3.js provides to work with hierarchical data. We'll use D3.js to created different kinds of trees, and also show treemap and pack visualizations.

Chapter 4, Visualizing Graphs, uses the force layout to visualize graphs of data. We'll use this D3.js API to visualize relations between Simpson characters in different and interactive ways. We'll also show a custom matrix visualization, which can be used to visualize a large matrix of interconnected relations.

Chapter 5, Working with Geo Data, shows one of the most interesting features of D3.js, that is, how to work with geographical data. We'll show you all the various map projections provided by D3.js and also how easy it is to manipulate and enrich maps through D3.js.

Chapter 6, Visualizing Streaming Data, explores different options on how you can use D3.js to visualize real-time streaming data. We'll show you how to receive information through websockets and visualize that information in different ways.

Chapter 7, Voronoi Diagrams and Heatmaps, shows two final ways of visualizing data. We'll show various Voronoi-based visualizations and approach, which you can use to generate art, using these Voronoi diagrams. In this chapter, we'll also show you a way to create heatmaps, which show a way to visualize occurrence data during a specific period of time.

Chapter 8, Custom Shapes and Paths and Using a Brush Selection, goes deeper into the tools provided by D3.js to create custom shapes and paths. We'll also explore the brush API provided by D3.js, which can be used to easily select elements from a visualization.

Chapter 9, ES6, TypeScript, and External D3.js Libraries, concludes this book by looking at how you can use D3.js together with ES6 and TypeScript, and we'll explore a couple of libraries build on top of D3.js that provide a number of standard charts out of the box.

What you need for this book

To work with the examples in this book, you don't need any special software requirements besides having Node installed and having an editor that you can use to explore and append the examples. The first chapter explains how to install and use these tools to run and extend the examples.

Who this book is for

This book is great for you if you are a JavaScript developer and want to start creating data visualizations. This book will explain all the steps you need to take to create beautiful interactive visualizations using D3.js and show you examples, which you can reuse and extend for your own purposes. This book will also explain how to prepare the data to be visualized.

Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "In this page, we also define a single div tag that has an id with a value output."

A block of code is set as follows:

<script> 
    (function() { 
        show(); 
    })(); 
</script>

Any command-line input or output is written as follows:

$ geo2topo -V
  2.0.0
$ toposimplify -V
  2.0.0

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text surrounded by quotes, or like this: "Just hit the Download button and click OK."

Warnings or important notes appear in a box like this.

Tips and tricks appear like this.

Reader feedback

Feedback from our readers is always welcome. Let us know what you think about this book—what you liked or disliked. Reader feedback is important for us, as it helps us develop titles that you will really get the most out of.

To send us general feedback, simply e-mail [e-mail], and mention the book's title in the subject of your message.

If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, see our author guide at www.packtpub.com/authors.

Customer support

Now that you are the proud owner of a Packt book, we have a number of things to help you to get the most from your purchase.

Downloading the example code

You can download the example code files for this book from your account at http://www.packtpub.com. If you purchased this book elsewhere, you can visit http://www.packtpub.com/support and register to have the files e-mailed directly to you.

You can download the code files by following these steps:

1. Log in or register to our website using your e-mail address and password.
2. Hover the mouse pointer on the SUPPORT tab at the top.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box.
5. Select the book for which you're looking to download the code files.
6. Choose from the drop-down menu where you purchased this book from.
7. Click on Code Download.

You can also download the code files by clicking on the Code Files button on the book's webpage at the Packt Publishing website. This page can be accessed by entering the book's name in the Search box. Please note that you need to be logged in to your Packt account.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR / 7-Zip for Windows
• Zipeg / iZip / UnRarX for Mac
• 7-Zip / PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Expert-Data-Visualization. We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

Downloading the color images of this book

We also provide you with a PDF file that has color images of the screenshots/diagrams used in this book. The color images will help you better understand the changes in the output. You can download this file from https://www.packtpub.com/sites/default/files/downloads/ExpertDataVisualization_ColorImages.pdf.

Errata

Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you find a mistake in one of our books—maybe a mistake in the text or the code—we would be grateful if you could report this to us. By doing so, you can save other readers from frustration and help us improve subsequent versions of this book. If you find any errata, please report them by visiting http://www.packtpub.com/submit-errata, selecting your book, clicking on the Errata Submission Form link, and entering the details of your errata. Once your errata are verified, your submission will be accepted and the errata will be uploaded to our website or added to any list of existing errata under the Errata section of that title.

To view the previously submitted errata, go to https://www.packtpub.com/books/content/support and enter the name of the book in the search field. The required information will appear under the Errata section.

Piracy

Piracy of copyrighted material on the Internet is an ongoing problem across all media. At Packt, we take the protection of our copyright and licenses very seriously. If you come across any illegal copies of our works in any form on the Internet, please provide us with the location address or website name immediately so that we can pursue a remedy.

Please contact us at [e-mail] with a link to the suspected pirated material.

We appreciate your help in protecting our authors and our ability to bring you valuable content.

Questions

If you have a problem with any aspect of this book, you can contact us at [e-mail], and we will do our best to address the problem.