Pie, 3-D, radar and doughnut charts

A chart can change type at any time. Turn the quarterly-sales column chart into a pie, and each slice shows one quarter's share of the year; the slices always add up to 100%.

A pie chart works only when:

• there is one data series only;
• the values are positive; and
• none of them are zero.

The book suggests at most seven categories, or the slices become too thin. A 3-D pie adds bevel, shadow and rotation: the angle of the first slice can be set from 0 to 360 degrees. Resize any chart by dragging a corner or border with the two-headed arrow.

Axes: a 2-D chart has a horizontal (category, X) axis and a vertical (value, Y) axis; negative values lie to the left of or below the origin. A 3-D chart adds a third, the depth (series, Z) axis.

Two more types:

• Radar charts compare the aggregate values of several series, such as each product's highest and lowest sales.
• Doughnut charts, like pies, show parts of a whole, but in rings, with a hole in the middle, and a doughnut can hold more than one series. They are harder to read than a pie.

Pie and doughnut charts have no axes.