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What is an area chart and when to use it?

Charts in general are representations that help make the visualization and analysis of data easier.

There are different models available, including area charts; this is one of the most used visualization types due to its ease of reproduction, interpretation and changes/trends comparisons that it offers.

The intention with this chart type is to bring practicality to data visualizations, primarily for searches that generate a lot of information: that is, when the numbers are extensive or need to be simplified for consumption.

This is a model that brings more objectivity, simplicity and clarity to the visual representation, providing faster outputs for visual information display.

What is an area chart

An area chart is basically a line chart, but where the area between the line and the axis is filled with one or more shading colors, depending on the purpose of the chart.

This filled area between the line and the axis indicates precisely the volume of what is being visually represented.

To reproduce this chart type, you can start with a simple area chart, then plot (connect) the data points on the Cartesian coordinate grid via a line, and finally fill the space below the lines with different colors.

This chart type is ideal for showing trends, displaying quantitative values over time periods, and changing the proportion of a total that each measured factor represents at a given point in time.

The communication here is delivered through general trends rather than individual numbers, which are compared to many data series.

Area chart types

Area (default / standard)

The standard area chart displays color-filled data in the space below the trend line. They are commonly applied when looking to display accumulated values over a given period of time.

Stacked area chart

Stacked area charts are used to represent cumulative totals as values or percentages captured over a period of time.

When creating a stacked area chart, the intent is to make it easier to view/compare events from part to whole, showing how each element is contributing to the grand total.

Sankey chart

The sankey chart is less common. We can generally understand it as a stacked chart whose baseline is shifted to the center. The arrangement (height) of each color represents the flow change over time and its length represents its duration.

Stepped area chart

The stepped area chart is used when representing trends, highlighting the decrease or increase of values over time. This type of area chart is extremely useful for showing price changes over time periods, for example.

When to use (and when not to use) area charts

Standard area charts showcase changes that happen over certain periods of time, trends, and continuity of a data category. In general, they are best employed when:

1.

There is data that needs to be expressed as a total;

2.

There are available time periods for making comparisons;

3.

The data indicates general trends and not individual values;

4.

The visualization can display multiple series of data related to each other, parts that are relative to a whole, or a cumulative series of values.

It is also important to evaluate when not to use area charts, as the information may not be well interpreted by the end-user. They are not ideal for showing how values change across a range of different categories. For this, it’s best to use a bar chart.

Besides this, if the difference between values is very small, data displayed in rows can be more effective at conveying information because this visualization type can be stretched to emphasize small differences.

Due to these characteristics, it is important to consider whether the area chart meets the main visualization requirements;

In this case, they would be to highlight a change, a total, and especially if there are cumulative changes over a specified period of time. If your data set does not meet these points, consider using another chart type instead.

Did you like this content? Learn more about data visualization and appropriate chart types in general in our blog.

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