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 4 – orthographic projections

For the next set of experiments in this chapter, we will switch gears and look at interactivity with orthographic projections (representing a three-dimensional map on a two-dimensional screen). A better visualization to illustrate these concepts is the entire globe instead of a single country. This experiment will start with http://localhost:8080/chapter-5/example-4.html and require a new datafile, which is provided for you. You will notice that the code base is almost identical, with the exception of three changes that we will outline here:

var height = 600; 
var width = 900; 
var projection = d3.geoOrthographic().clipAngle(90); 
var path = d3.geoPath().projection(projection); 

First, we will change our d3.geo projection from d3.geoMercator to d3.geoOrthographic. We also have an additional setting to configure: the clipAngle at 90...