Axis const (reference) lines allow you to highlight a value of the scale on the chart walls and the polar radar plot area. You can add an arbitrary number of const lines to the axis by using the "Add" button. The following settings apply to axis const lines:

Value- controls the value of the reference line. You can enter any numeric / date time value which will be parsed.

Text - controls the text displayed at the const line.

Text Offset X and Text Offset Y - control the text offset relative to the origin point of the text selected by text alignment.

Text Alignment - controls the position of the text relative to the const line.

Stroke Style - invokes the stroke style dialog allowing you to modify the stroke of the reference line.