Book Image

Learn Chart.js

By : Helder da Rocha
Book Image

Learn Chart.js

By: Helder da Rocha

Overview of this book

Chart.js is a free, open-source data visualization library, maintained by an active community of developers in GitHub, where it rates as the second most popular data visualization library. If you want to quickly create responsive Web-based data visualizations for the Web, Chart.js is a great choice. This book guides the reader through dozens of practical examples, complete with code you can run and modify as you wish. It is a practical hands-on introduction to Chart.js. If you have basic knowledge of HTML, CSS and JavaScript you can learn to create beautiful interactive Web Canvas-based visualizations for your data using Chart.js. This book will help you set up Chart.js in a Web page and show how to create each one of the eight Chart.js chart types. You will also learn how to configure most properties that override Chart’s default styles and behaviors. Practical applications of Chart.js are exemplified using real data files obtained from public data portals. You will learn how to load, parse, filter and select the data you wish to display from those files. You will also learn how to create visualizations that reveal patterns in the data. This book is based on Chart.js version 2.7.3 and ES2015 JavaScript. By the end of the book, you will be able to create beautiful, efficient and interactive data visualizations for the Web using Chart.js.
Table of Contents (14 chapters)
Title Page
Copyright and Credits
About Packt

Stacked area charts

A line chart could be used to show how much CO2 that each country releases in the atmosphere each year. It would reveal if a country's emissions were increasing, stable, or decreasing, but such a line chart would not be very useful to show the total amount of CO2 released in the air, and how each country contributes to this total. You can display this kind of information using a stacked area chart.

There is no special area type chart in Chart.js. Instead, you can create a simple overlapping area chart configuring the fill properties for each dataset in a line chart. To create a stacked area chart, you will need to set the stacked property to true in the x and y-axes.

Let's try an example. We will use a JSON file containing data about carbon emissions (in kilotonnes) from selected countries from 1960 to 2014. It's based on a CSV file containing data for all countries, which is available for download from the World Bank public database. I created a JSON Version of this file...