Intro

Column charts are used to compare multiple values over time, or values that have an intrinsic order (such as age, ranges, or ratings). The idea is to convey a progression or a trend, which is best represented by showing these values on the horizontal axis.

Column Chart vs. Bar Chart

Use a column chart if:

• Category items represent a time series. The natural orientation for time is from left to right.
• Category items have an intrinsic order.

Use a bar chart if:

• Category items do not have an intrinsic order (such as products, projects, or countries).

If you use a column chart for categories that do not have an intrinsic order, there is a high probability that the labels will be displayed at 45°, forcing truncation and making them hard to read. However, this will not happen with a bar chart, as illustrated below.

Time Axis

If the horizontal axis represents time, you can use the time axis.

The time axis has three main advantages:

• It allows you to display dates and times in a responsive manner.
• All the complexity involved with formatting the axis labels is automatically taken care of.
• The physical spacing between the data points accurately represents the time scale, as opposed to being equidistant.

If you do not need the advantages offered by the time axis, you can use a horizontal categorical axis instead.

Labels

When space is limited, the labels are displayed at 45°, making them difficult to read. Here’s how to avoid this:

• First, check that the category has an intrinsic order. If not, consider using a bar chart instead.
• If the category is time-based, use a time axis.
• If it is not possible to use a time axis, the only solution is to abbreviate the labels.

Resources