Bar charts are one of the most common and useful data visualizations. In this chapter, we will learn how to create bar charts using D3. We will see how to bind data to DOM elements, use scales and axes, and customize the appearance of the chart.

Sample Data

For this chapter, we will use a simple dataset:

javascript

Setting up the SVG

First, we set up the SVG area where the bar chart will be drawn:

javascript

Scales

We need scales to map the data to the dimensions of the SVG.

X Scale

We use a band scale for the X axis, as we are working with categories:

javascript

Y Scale

For the Y axis, we use a linear scale:

javascript

Axes

We create and add the X and Y axes using the defined scales:

javascript

Creating the Bars

Now we bind the data to rect elements to create the bars of the chart:

javascript

Customizing the Bar Chart

We can customize the bar chart to make it more attractive. For example, adding labels to the bars to show the values:

javascript

And we can add CSS styles to enhance its appearance:

style.css

css

Summary

In this chapter, we learned how to create a bar chart in D3. We started with the basic setup of the drawing area and then created the scales and axes. From there, we bound the data to rect elements to form the bars and customized the chart by adding labels and styles.

Bar charts are fundamental for many data visualization applications, and now you have the knowledge to create and customize your own bar charts using D3.

In the next chapter, we will explore how to create line charts for temporal or sequential data visualizations.