The area chart in Looker Studio

The area chart is used to represent quantitative values over time, helping you detect trends and volumes. It is similar to time series charts, but this one requires the selection of a breakdown dimension. In other words, apart from the time dimension, we will have one more.

Imagine that you have an ecommerce business, and you want to represent the volume of sales over time by product category. In this case, the product category would be the breakdown dimension.

If your breakdown dimension includes many categories, it can be difficult to interpret. Dimensions like age, which often have many distinct values, are not recommended for this type of visualisation (unless you use age ranges).

1. Example

We are going to use the Spotify dataset and create an area chart showing the number of songs by their release date and by mode (major or minor). To do this, we’ll add a stacked area chart.

Visit the post on how to add charts to your report in Looker Studio, if you need a refresher.

In the chart’s Set-up, we’ll select release_date as the dimension and mode as the breakdown dimension. Our metric will be Record count, as we want the number of songs, and this counts the number of rows (since there is one unique song per row).

This is how our area chart would look with the configuration above.

Quite hard to read, right?

Let’s change the date format by clicking on the pencil icon to the left of our release_date dimension. By default, it will show that the release date is of Date type.

We need to change Date to Year and Month as the data type.

The result is a bit better, but considering that most songs are from recent years, we’ll filter the chart to show data from 2016 onwards. I chose 2016 because when reviewing the dataset, I saw that 3 of the top 10 songs are from that year.

By changing the Default date range to Custom, we can select a specific date range for the chart.

In the window in the above image, you can select the date range for the area chart.

Here’s the result.

Much better, but for the purpose of explaining what comes next, I think it’s best to limit the data starting from January 2021. The chart will look like this.

Now, what do you think of this chart? Which mode would you say has had more songs since 2021: major or minor?

2. Specific Customisation Options for the Chart

It’s worth noting that this is a stacked chart, meaning the minor mode does not start from the 0 on the left axis, but rather from the line of the major mode. In May 2022, 75 songs were released, 42 of which were in the major key and 33 in the minor key. Overall, there are more songs in the major scale than in the minor.

If you want to see the chart without stacking, you need to select a regular area chart (without “stacked” in the name), or you can go to Style and uncheck the box labeled Show Stack.

Here’s how it would look.

If you want to stack it to 100%, in addition to selecting Show Stack, you also need to activate 100% Stacking.

I like to stack it to 100% when I want to see the percentage share of each category. The only limitation is that if you view it by percentage, you won’t see the trend in absolute values.

This type of chart has other options, such as adding reference lines or bands, which you can find in the Style tab.

How do you prefer to use the area chart? Stacked, unstacked, or stacked to 100%?

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