Preface

This book explores the JavaScript library D3. js and its ability to help us create maps and amazing visualizations. You will no longer be confined to third-party tools in order to get a nice looking map. With D3. js, you can build your own maps and customize them as you please. This book will go from the basics of SVG, Canvas, and JavaScript, through to data trimming and modification with TopoJSON. Using D3. js to glue together these key ingredients, we will create very attractive maps that cover many common use cases, such as choropleths, data overlays on maps, interactivity, and performance.

What this book covers

Chapter 1, Gathering Your Cartography Toolbox, starts off with a working example in order to get a feel for what you will be able to build by the end of the book.

Chapter 2, Creating Images from Simple Text, dives into SVG and its common geographic shapes and attributes. Showcases how one can animate with vectors.

Chapter 3, Producing Graphics from Data - the Foundations of D3, reads about the foundations of the different states within D3 and how it interacts with the DOM.

Chapter 4, Creating a Map, presents our first examples of building maps. The chapter covers basic events and extending past map borders, as we intertwine the map with other data sets.

Chapter 5, Click-Click Boom! Applying Interactivity to Your Map, dives into all the types of interactions you can have with a map in your browser. This includes hovering, panning, zooming, and so on.

Chapter 6, Finding and Working with Geographic Data, shows how to find and utilize geospatial data.

Chapter 7, Testing, describes how to structure your codebase in order to have reusable chart components that are easily unit tested and primed for reuse in future projects.

Chapter 8, Drawing with Canvas and D3, shows how to get started with Canvas. You'll learn to draw, animate, and use the D3 life cycle for data updates.

Chapter 9, Mapping with Canvas and D3, describes how to map and animate thousands of points with Canvas, as well as how Canvas animation compares to SVG animation.

Chapter 10, Adding Interactivity to Your Canvas Map, guides you through the process of adding interactivity to Canvas, a process that requires a little more thought and attention than with SVG.

Chapter 11, Shaping Maps with Data – Hexbin Maps, explains how to build hexbin maps with D3 - a great way to show geospatial point data.

Chapter 12, Publishing a Visualization with GitHub Pages, shows you how to get your visualization online in a simple and fast way.

What you need for this book

The following are the requirements for this book; these work on macOS, Windows,
and Linux:

• A D3.js library v5.0.0
• Node.js v8.9.0+
• npm for example, v5.5.1+

Who this book is for

This book is for people with at least a basic knowledge of web development (basic HTML/CSS/JavaScript). You don't need to have worked with D3.js before.

Conventions

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Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The width and height are the only properties the canvas element has."

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context.save();
context.translate(140, 190);
context.fillRect(0, 0, 60, 30);
context.restore();

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 like this: "You go to https://github.com/, click on Sign in, and follow the steps."

Warnings or important notes appear in a box like this.

Tips and tricks appear like this.

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