Advanced Report Design - Professional SQL Server 2005 Reporting Services - page 233

Area and Line Charts
An area chart plots the values of each point and then draws a line from point to point to show the pro-
gression of values along the series. This is an effective method for analyzing trends and works well
when values tend to climb, decline, or remain level in the series. This type of chart is accurate when data
exists for all category values on the X-axis. It typically doesn't work well to express a series of values
that are not in a relatively uniform plane. Figure 6-67 is an example of an area chart.
Figure 6-67
The line chart is a variation of an area chart using a line or ribbon rather than a solid area. The line chart
works better than the area chart for comparing multiple categories for a series of values because one
layer may obscure another in the area view. In the preceding example, the area chart works because val-
ues are sorted in a way that larger values are in the background and other points in the foreground are
smaller; the trend increases back to front.
Pie Charts
A pie chart is an excellent tool for comparing proportional values. Display options for a pie chart include
exploded and 3-D views. The 3-D pie chart in Figure 6-68 clearly shows that Touring Bike sales are a
small percentage, around 10% of total Bike Sales, and that Road Bike sales account for about half of the
total sales. I call this piece “PacMan Gets a Root Canal.”
A doughnut chart is a pie chart with a hole in it. This is a rather profound concept, isn't it? Actually, in
cases where there may be several smaller slices, the donut chart can be a little easier to read and pro-
vides a little variation on an age-old chart theme. The chart shown in Figure 6-69 is the same as the pre-
vious chart without the exploded view and a legend showing the series labels.