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

Line and area charts

Line charts are used to display a correlation between two sets of data, where one of the sets should contain categorical or ordered data (ascending or descending). The most common application of a line chart is the time series, where the ordered set consists of instants of time. If arbitrary categories are used, it should be possible to establish some kind of connected sequence with them (for example, an ordered sequence of steps).

Line charts display estimates. The points that correlate the datasets are connected with straight or curved lines that represent estimated values. Line charts can be used to predict intermediate values and reveal trends.

Creating a simple line chart

Just like the bar chart, you need to load the Chart.js JavaScript library, place a <canvas> object somewhere in the <body> of your page, and create a new chart referring to the ID of the canvas, and an object with the chart data. The chart object should specify line as the chart type....