Three years ago, we challenged you to create a square area or waffle chart. Many who completed that challenge commented that this was their first time making a square area chart—or, more broadly, it was their first time making a unit chart. That’s because unit charts aren’t frequent in the data visualization world.

In a unit chart, a single symbol represents a specific quantity: one unit, ten units, or any reasonable amount the designer chooses. The symbols themselves could be geometric shapes, icons, or images. You might have seen unit charts before: think of ISOTYPE charts, waffle charts, or some other chart with small symbols.

“Isotype, unit chart, waffle chart” results from Google image search

As you scanned the above unit charts, you likely noticed the breadth of this chart type—they all look so different. That said, there are a few common considerations when choosing a unit chart. I’ll briefly outline a couple of important ones below and encourage you to read further through the resource section.

They are engaging. Compared to the standard bar chart, unit charts tend to be more inviting. As Jon Schwabish says in his book Better Data Visualizations, they “lend themselves to a more human connection.” For instance, if we use silhouettes of individuals or faces, it reminds us that we aren’t just communicating numbers and data but rather valuable information about individuals. It’s similar to the difference between saying 70% of people versus 7 out of 10 people.
They are polarizing. Critics often argue that unit charts are full of chart junk. They disagree with the concept of showing data individually or in units, especially when it could be displayed in a simpler, aggregated chart. Some even find the use of icons and images to be childish. On the other hand, that same use of recognizable symbols can make unit charts intuitive enough for most audiences to easily process.

You can see real-world examples and learn more about these charts, along with the latest research, by checking out the resource section below.

Enjoy charting this month...in units!

The challenge

Pick a dataset that can be shown in units or symbols. Typically, this means some sort of discrete or countable data set. Whatever you decide to visualize, the goal is to explore something new and experiment with symbols this month.

If you need help finding data, check out this list of publicly available data sources. Share your creation in the community by July 31st at 3PM PDT. If there is any specific feedback or input that you would find helpful, include that detail in your commentary.

Related resources

Here are a few related resources (not a comprehensive list). If you are aware of other good ones, please share in your submission commentary.

We are excited for you to experiment with unit charts this month!