Book Image

D3.js Quick Start Guide

By : Matthew Huntington
Book Image

D3.js Quick Start Guide

By: Matthew Huntington

Overview of this book

D3.js is a JavaScript library that allows you to create graphs and data visualizations in the browser with HTML, SVG, and CSS. This book will take you from the basics of D3.js, so that you can create your own interactive visualizations, to creating the most common graphs that you will encounter as a developer, scientist, statistician, or data scientist. The book begins with an overview of SVG, the basis for creating two-dimensional graphics in the browser. Once the reader has a firm understanding of SVG, we will tackle the basics of how to use D3.js to connect data to our SVG elements. We will start with a scatter plot that maps run data to circles on a graph, and expand our scatter plot to make it interactive. You will see how you can easily allow the users of your graph to create, edit, and delete run data by simply dragging and clicking the graph. Next, we will explore creating a bar graph, using external data from a mock API. After that, we will explore animations and motion with a bar graph, and use various physics-based forces to create a force-directed graph. Finally, we will look at how to use GeoJSON data to create a map.
Table of Contents (10 chapters)

Styling an element

The appearance of any tag inside an <svg> can be styled with the following attributes (the following are the attributes with example values):

  • fill=red or fill=#ff0000 will alter the color of the shape.
  • stroke=red or stroke=#ff0000 will alter stroke color. Stroke is a line that surrounds each element.
  • stroke-width=4 will adjust the width of the stroke.
  • fill-opacity=0.5 will adjust the transparency of the fill color.
  • stroke-opacity=0.5 will adjust the transparency of the stroke color.
  • transform = "translate(2,3)" will translate the element by the given x, y values.
  • transform = "scale(2.1)" will scale the size of the element by the given proportion (for example, 2.1 times as big).
  • transform = "rotate(45)" will rotate the element by the given number of degrees.

Let's style the circle we positioned previously:

<circle...