Book Image

Learning D3.js 5 Mapping - Second Edition

By : Thomas Newton, Oscar Villarreal, Lars Verspohl
Book Image

Learning D3.js 5 Mapping - Second Edition

By: Thomas Newton, Oscar Villarreal, Lars Verspohl

Overview of this book

D3.js is a visualization library used for the creation and control of dynamic and interactive graphical forms. It is a library used to manipulate HTML and SVG documents as well as the Canvas element based on data. Using D3.js, developers can create interactive maps for the web, that look and feel beautiful. This book will show you how build and design maps with D3.js and gives you great insight into projections, colors, and the most appropriate types of map. The book begins by helping you set up all the tools necessary to build visualizations and maps. Then it covers obtaining geographic data, modifying it to your specific needs, visualizing it with augmented data using D3.js. It will further show you how to draw and map with the Canvas API and how to publish your visualization. By the end of this book, you'll be creating maps like the election maps and the kind of infographics you'll find on sites like the New York Times.
Table of Contents (13 chapters)
6
Finding and Working with Geographic Data

Writing testable code

There are dozens of factors to consider when creating visualizations. Every design will have its own set of unique requirements and configuration capabilities to consider. If you build on the reusable pattern outlined by Mike Bostock, you will have a great framework to start with.

When working with data visualizations, we will have some form of data manipulation or logic that must be applied to incoming data. There are two notable best practices we can leverage to test and validate these operations. They are explained in the following sections.

Keeping methods/functions small

Small functions mean low cyclomatic complexity. This means there are fewer logic branches in each function and, therefore, fewer...