Microsoft Office Tutorials and References
In Depth Information
Working with Chart Axes
You can, of course, override this automatic behavior and specify your own minimum, maximum,
major unit, minor unit, and cross-over for any value axis. You set these specifications by right-clicking
on the axis and selecting Format Axis. This will activate the Format Axis dialog box shown in
Figure 7-18. Use the settings under Axis Options to customize the axis as needed.
Figure 7-18: The Axis Options tab of the Format Axis dialog box.
A category axis does not have a scale because it displays arbitrary category names. For a
category axis, the Axis Options tab of the Format Axis dialog box displays a number of
other options that determine the appearance and layout of the axis.
Adjusting the scale of a value axis can dramatically affect the chart’s appearance. Manipulating the
scale, in some cases, can present a false picture of the data. Figure 7-19 shows two line charts that
depict the same data. The top chart uses Excel’s default axis scale values, which extend from 8,000 to
9,200. In the bottom chart, the Minimum scale value was set to 0, and the Maximum scale value was
set to 10,000. A casual viewer might draw two very different conclusions from these charts. The top
chart makes the differences in the data seem more prominent. The lower chart gives the impression
that not much change has occurred over time.
The actual scale that you use depends on the situation. There are no hard-and-fast rules regarding
setting scale values, except that you shouldn’t misrepresent data by manipulating the chart to prove
a point that doesn’t exist. In addition, most agree that the value axis of a bar or column chart should
always start at zero (and even Excel follows that rule).