Datum Lines

Add horizontal and vertical datum lines to plots.

Figure 1.

A datum line can be hidden or displayed on a plot by activating the Datum check box.

You can specify a math expression to define the display of a datum line.

Use the drop-down menu next to the Datum check box to switch between horizontal and vertical datum lines.

Datum lines can be cut, copied, pasted, or added.


Create a label for a datum line.
Select the font icon to change the font type, style, size.
Under Display, select an icon that corresponds to the label location you want to set.
Select Mouse Over only display the label when you mouse over it with your cursor.


Positions the datum line on the X or Y axis.
Enter a value in the Position field.
The value entered can be any of the following:
  • A single value.
  • A math expression that returns a single value (without curly brackets, {}).
  • A math expression as a function of x or y, with x or y being the horizontal or vertical axes values, respectively.
Select the axis from the Axis menu.

Positions the datum line to the maximum value of all visible curves.

Positions the datum line to the minimum value of all visible curves.
Note: The Max/Min are only available for horizontal datum lines in the XY plot type.

Line Attributes

Sets the attributes of a datum line.

Click Use Preferences to use the preferences set in the preferences.mvw file.