Part III: Creating Charts and Other Visualizations
The data used in the chart resides in A2:B8. When the chart was created, Excel made a
guess as to which categories belong to the secondary chart. In this case, the guess was to
use the last three data points for the secondary chart—and the guess was incorrect.
To correct the chart, right-click any of the pie slices and choose Format Data Series. In the
Format Data Series task pane, select the Series Options icon and make the changes. In this
example, we chose Split Series by Position and specified that the second plot contains four
values in the series.
Another pie chart subtype is called a doughnut chart. It’s basically a pie chart with a hole in
the middle. Unlike a pie chart, however, a doughnut chart can display multiple series.
XY (scatter) charts
Another common chart type is an XY chart (also known as scatter grams or scatter plots).
An XY chart differs from most other chart types in that both axes display values. (An XY
chart has no category axis.)
This type of chart often is used to show the relationship between two variables.
Figure 20.27 shows an example of an XY chart that plots the relationship between sales
calls made (horizontal axis) and sales (vertical axis). Each point in the chart represents one
month. The chart shows that these two variables are positively related: months in which
more calls were made typically had higher sales volumes.
Although these data points correspond to time, the chart doesn’t convey any time-related information. In other
words, the data points are plotted based only on their two values.
Area charts
Think of an area chart as a line chart in which the area below the line has been colored in.
Figure 20.28 shows an example of a stacked area chart. Stacking the data series enables you
to see the total clearly, plus the contribution by each series.
Figure 20.29 shows the same data, plotted as a 3-D area chart. As you can see, it’s not an
example of an effective chart. The data for products B and C is partially obscured. In some
cases, the problem can be resolved by rotating the chart or using transparency. But usually
the best way to salvage a chart like this is to select a new chart type.
