The system variables !X, !Y, and !Z, are structures that affect the appearance and scaling of the three axes. The fields for !X are described here. !Y and !Z have identical fields with identical meanings and usage.

In addition, almost all fields have corresponding keyword parameters, with identical function, but with temporary effect. For example, to suppress the minor tick marks on the x-axis using the !X system variable:

!X.Minor = -1

while to suppress them in the call to PLOT:

PLOT, X, Y, XMinor = -1

The name of the keyword parameter is simply the name of the system variable field, prefixed with the letter X, Y, or Z.

The fields for the !X system variable are explained in the following sections.