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

Transform

The transform allows you to change your visualization dynamically and is one of the advantages of using SVG and commands to draw shapes. Transform is an additional attribute you can add to any of the elements we have discussed so far. Two important types of transform when dealing with our D3 maps are:

  • Translate: Move the element
  • Scale: Adjust the coordinates for all attributes in the element

Translate

You will likely use this transformation in all of your cartography work and will see it in most D3 examples online. As a technique, it's often used with a margin object to shift the entire visualization. The following syntax can be applied to any element:

transform="translate(x,y)" 

Here, x and y are...