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 5 – adding points of interest

So far, everything we have done has involved working directly with the geographic data and map. However, there are many cases where you will need to layer additional data on top of the map. We will begin slowly by first adding a few cities of interest to the map of Mexico.

This experiment will, again, require us to start with example-3.html. The complete experiment can be viewed at: http://localhost:8080/chapter-4/example-6.html.

In this experiment, we will add a text element to the page to identify the city. To make the text more visually appealing, we will first add some simple styling in the <style> section:

text{ 
  font-family: Helvetica; 
  font-weight: 300; 
  font-size: 12px; 
} 

Next, we need some data that will indicate the city name, the latitude, and longitude coordinates. For the sake of simplicity, we have added...