Add a Horizontal Datum Line

  1. From the Line, Bar, Complex, Polar, Vector, or Radar Chart ribbons, Datums tool group, click the Add Horizontal Datum Lines tool.
    Figure 1.

  2. Select the point on the curve to add the datum line to and left-click.
    The datum line is added to the curve and labeled "Datum 'n'".
  3. Click Esc to exit the datum tool and perform other functions.