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 6 – adding visualizations as a point of interest

For our final experiment, we will layer visualizations on top of visualizations! Starting from where we left off at http://localhost:8080/chapter-4/example-6.html, we will add a fictitious column to the data to indicate a metric of tequila consumption (the final version can be seen at http://localhost:8080/chapter-4/example-7.html):

name,lat,lon,tequila 
Cancun,21.1606,-86.8475,85,15 
Mexico City,19.4333,-99.1333,51,49 
Monterrey,25.6667,-100.3000,30,70 
Hermosillo,29.0989,-110.9542,20,80 

With just two more lines of code, we can have the city points portray meaning. In this experiment, we will scale the radius of the city circles in relation to the amount of tequila consumed:

var radius = d3.scaleLinear().domain([0,100]).range([5,30]);  

Here, we will introduce a new scale that linearly distributes the input values...