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D3.js Quick Start Guide

D3.js Quick Start Guide

By : Huntington
5 (1)
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D3.js Quick Start Guide

D3.js Quick Start Guide

5 (1)
By: 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)
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Creating the color scale to map labels to colors

Now, we want to map the label properties of our dataset to colors, instead of random numbers, like in the previous section. We can come up with our own color scheme, or we choose one of D3's sets of colors from https://github.com/d3/d3-scale-chromatic#categorical.

If we want to, we can see that these color schemes are just arrays. Temporarily, add the following to the bottom of app.js:

console.log(d3.schemeCategory10)

The following content will be displayed:

Consequently, we can use a color scheme when setting a range. Replace the previous console.log() statement with the following:

var colorScale = d3.scaleOrdinal();
colorScale.range(d3.schemeCategory10);

We can generate an array of labels for the domain by using JavaScript's native map function. Add the following to the bottom of app.js:

colorScale.domain(dataset...

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