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

Experiment 1 – adjusting the bounding box

Now that we have our foundation, let's start with our first experiment. For this experiment, we will manually zoom into a state of Mexico using what we learned in the previous section. The code can be found in example-2.html (http://localhost:8080/chapter-4/example-2.html); however, feel free to edit example-1.html to learn as you go.

For this experiment, we will modify one line of code:

  var b = path.bounds(states.features[5]); 

Here, we are telling the calculation to create a boundary based on the sixth element of the features array instead of every state in the country of Mexico. The boundaries data will now run through the rest of the scaling and translation algorithms to adjust the map to the one shown in the following screenshot:

We have basically reduced the min/max of the boundary box to include the geographic coordinates...