A reference line is a line intersecting the chart area from a given point on the measure axis.
You can use a reference line to indicate a certain level of chart data. The reference line is only drawn if it falls within the current range of the measure axis. You can have several reference lines in the same chart.
Reference lines are available in the following visualization types:
- Bar chart
- Box plot
- Distribution plot
- Line chart
- Scatter plot
- Waterfall chart
Reference line expression
You can either set the reference line expression to an absolute numeric value, or enter an arbitrary numeric expression.