5.6. Stack Column Charts

Stack Column Chart

A stack column chart is a derivative of a column chart in which each vertical column comprises a stack of bars. Each selected row in the data table is represented by a component of a chart column. For a two-dimensional stack column chart, the categories are plotted on the X-axis and the values on the Y-axis. The value column, which must be numeric, determines the length of each bar component. A third column, known as the sum-by column, represents a group of values for each category. A stack for a given category value is built up stacking the sum-by values for that category value. Each stack component of a chart column has a distinct sum-by value denoted by a distinct color. Each row in the data table must have a unique pair of values on both the category and sum-by columns. Components with negative values are separated from components with positive values and they are stacked up in the negative direction below the X-axis.

In our example above, we have chosen types of drink as category value and day representing the sum-by values. Another independent category (to be displayed on the Z-axis) may be optionally specified based on a fourth column as a data series. In such a case, each row in the data table must have a unique triplet of values on the category, sum-by and data series columns. In a two-dimensional chart, the entire data series for a single category is displayed side-by-side in the XY plane. In a three-dimensional stack column chart, the data series is displayed along the Z-axis.

5.6.1. Data Mapping

In stack column charts, each category is further subdivided into components. Hence, there is an additional sum-by option used to determine the sum-by values for the chart.

Mapping Options for Stack Column Charts

The data mapping options are as follows:

Data Series:

Allows you to choose a data column whose distinct values will determine the number of data series in the chart. Each element in a data series is drawn using the same color.

Category (X):

Allows you to choose a data column whose distinct values determine the categories. Values from this data column are used to calibrate the X-axis. Each category in a data series is drawn as a distinct column in the chart.

Sum-by:

Allows you to choose a data column whose distinct values determine the components in each category. Each distinct value in this column determines a distinct stack component of a column.

Value (Y):

Choose a data column to provide values for each category.

2nd value:

Add a second value to create a combination chart.

2nd Series:

Choose another column to be series for the secondary chart. This option is applicable only if the secondary chart is an overlay chart.

Combo:

Choose the chart type for the secondary chart. For stack column charts the combo options are Line, Stack Area, and Overlay.

The data mapping also allows you to transpose the data (in other words: to select several columns for a single category). To learn more about data transposition, please see Section 5.1.1 - Data Transposition.

Stack column charts have a unique combination option which allows users to plot a second value as a stack area chart. Both values share the same category and sum-by values. This chart can compare component based categories for different values in the data.

Stack Column-Stack Area Combination Chart

With this combination chart you can specify to hide particular sum-by component in the chart to achieve a strip area effect.