Area chart

An area chart is essentially a line chart with the section below the line shaded or color-filled. This can be very useful when you want to emphasize both the absolute value of a time series and the trend pattern. The distinct fill below the line gives it a peak-and-trough design that makes it easy for users to recognize the absolute performance alongside the trend. The following screenshot shows an area chart for the same yearly sales data we plotted a line chart on earlier:

Figure 8.20 – Area chart of sales over a period

Things can be a bit tricky with using area charts for two or more metrics. See Figure 8.21 of the area chart of sales and expenses. Notice that the user could be confused about the actual value of sales and likely interpret it wrongly as it is stacked on the expense chart:

Figure 8.21 – Area chart of sales and expenses

We will move on, now, to another chart.