About area charts
An area chart displays data values as a set of points connected by a line, with the area shaded below the line. You use an area chart to present data that occurs over a continuous period of time. For example, you can use an area chart to view the percentage of orders and the corresponding unit volume for trains, ships, and planes over three months.
Stacked area chart
A stacked area chart consists of multiple series stacked vertically, as shown in Figure 7-4. The example shows that the stacked area chart is suitable for the data because the chart displays totals for all series as well as the proportion that each series contributes to the total. The height of the top line shows the total value for each category, for each quarter in this example. Each shaded area represents the sales amount for a specific region.
Figure 7-4 Area chartOverlay area chart
Overlay area charts show areas from each series independent of each other. The areas appear by joining the values for the series. In an overlay area chart, the areas of multiple series overlap, as shown in Figure 7-5. As the example shows, this chart subtype is not suitable for showing multiple series if the data values overlap. Use an overlay area chart if you want to show only one series, for example, only sales for Asia.
Figure 7-5 Overlay area chartPercent stacked area chart
In a percent stacked area chart, multiple series are stacked vertically and the values appear as a percentage of the total. Figure 7-6 shows the sales values in percentages instead of the actual numbers as shown in the previous area charts.
The percent stacked area chart is meaningful only when displaying and comparing multiple series. If displaying only one series, the percent stacked area chart appears as in the example shown in Figure 7-7. The sales percentage of one region compared to the whole is 100%.