By default, there is only one scale on an axis, and all measures are shown on this scale. There might be times though, when the measures are of completely different magnitudes, or use different units. Then you might benefit from using more than one scale on the axis to visualize the measures.
As an example, imagine a bar chart containing two bars, each of the bars representing a certain column. One bar represents the total precipitation during a month, and another bar the average temperature. These two measures probably differ a lot, and might have need for two scales on the value axis.
The measures are based on your settings on the color axis. That is, the colors on the color axis can represent either different columns (short/wide data) or categories within a column (tall/skinny data).
There are two options to add more scales, Dual scales and Multiple scales. They are supported in bar charts, line charts, combination charts (in combination charts, the Series by axis is used for the coloring settings), and scatter plots.
Dual scales
When you use dual scales, there is one scale to the left and one scale to the right on the Y-axis/Value axis. Each of the scales can be shared by more than one measure.
For example, in the bar chart below, two columns share the scale to the left. To the right, another scale is used for the third column, because the unit is different and the values are of totally different magnitudes.
For information about how to assign measures (columns or categories) to each of the two scales, see the Y-axis/Values page of the properties for the visualization type in question.
Multiple scales
When you use multiple scales, by default you get one scale for each color that is defined on the color axis. This means that no scales are shared.
An example of a bar chart with three scales is shown below. The scales are differentiated by their colored scale labels.
To specify which side of the bars a certain scale should be located, see the Y-axis/Values page of the properties for the visualization type in question.
For a trellised visualization, it is possible to display one scale per trellis panel instead of per color.
Moreover, in a line chart, you have the option to display lines normalized, so that all lines are shown on a scale with the maximum value set to 100%, and the minimum value to 0%.
Note: You can also make individual settings for each scale, see the Y-axis/Value Axis page of the properties for the visualization type in question.
See also:
Bar Chart Properties – Value Axis
Line Chart Properties – Y-axis
Combination Chart Properties – Y-axis
Scatter Plot Properties – Y-axis