Adding Reference Lines to Graphs :: SAS(R) 9.3 ODS Graphics Designer: User's Guide

About Adding Reference Lines

When you add a reference line to a graph, the line is placed in a location near the cursor. A dialog box appears in which you can specify the position value and other settings. After you add the reference line, you can reposition line.

ODS Graphics Designer provides the following types of lines. Each type is identified by a unique icon in the user interface:

Icon	Description
	Creates a horizontal reference line that is parallel to the X axis and perpendicular to the Y axis at a Y intercept.
	Creates a vertical reference line that is parallel to the Y axis and perpendicular to the X axis at an X intercept.
	Creates a horizontal or vertical drop line from a point to an axis.
	Creates a straight line that is defined by a point and a slope.

Add a Reference Line to a Graph

The graph cell in which you add a reference line must already contain at least one plot. The line is overlaid on the plot.

To add a reference line:

Add a reference line the same way you would add any other plot. For instructions, see Add a Plot to a Graph.

Note: The line is placed in a location near the cursor.

The Assign Data dialog box appears.
Specify the data parameters for the line. The parameters vary with the type of line that you are adding. Here are the parameters that are specific to each type of line:

Note: The default X and Y settings depend on where the mouse button is released when you add the line.

Horizontal reference line

In the Y text box, specify the Y intercept for the line, or accept the default value.

Vertical reference line

In the X text box, specify the X intercept for the line, or accept the default value.

Drop line

In the X and Y text boxes, specify the coordinates for the point of reference.

From the Drop to list box, select the axis to which the line is dropped. A drop line is drawn perpendicular from the specified point to the X or Y axis.

Line with a specified slope

In the X and Y text boxes, specify the coordinates for the point of reference.

In the Slope text box, specify a slope for the line. A slope value of zero creates a horizontal line that is parallel to the X axis. A slope value of infinity creates a vertical line that is parallel to the Y axis. To create a vertical line, specify a decimal point (.) as the slope.

The line is drawn based on the specified point and the specified slope of the line that passes through that point.

Note: You cannot add this type of line to a plot if the plot's axis has date or time values.
(Optional) In the Label text box, specify a label for the line. This text box is available only for horizontal and vertical reference lines.
(Optional) In the Name text box, specify a descriptive name for the line.
If an X2 or Y2 axis has been associated with one or more plots in the cell, select either from the Axis list box to associate the line with the respective axis.
Click OK.

Reposition a Reference Line

After you add a line, you can move the line to a different location. When you position the cursor over the line, the cursor changes to a two-headed arrow

. You can then click and drag the line to the new location.

For a more precise position, you can use the Assign Data dialog box.

Note: You cannot move a sloped line by using the click-and-drag method. You must use the Assign Data dialog box.

To reposition a line by using the Assign Data dialog box:

Right-click the line that you want to move, and select Assign Data. The Assign Data dialog box appears.

Alternatively, right-click anywhere in the plot area, and select Assign Data. Then, in the Assign Data dialog box, select the line that you want to move from the Plot list box.
Specify the parameters for the position that you want. For a description of these parameters, see Add a Reference Line to a Graph.
Click OK.

Change the Length of a Drop Line

When you position the cursor at the tip of a drop line, the cursor changes to a double arrow cursor is a double arrow

. You can then click and drag to lengthen or shorten the line.

For a more precise length, you can use the Assign Data dialog box.

Right-click the line that you want to modify, and select Assign Data. The Assign Data dialog box appears.

Alternatively, right-click anywhere in the plot area, and select Assign Data. Then, in the Assign Data dialog box, select the line that you want to modify from the Plot list box.
Change the X parameter to modify a horizontal drop line, and the Y parameter to modify a vertical drop line. For a description of these parameters, see Add a Reference Line to a Graph.
Click OK.