The function plenv is used to define the scales and axes for simple graphs. plenv starts a new picture on the next subpage (or a new page if necessary), and defines the ranges of the variables required. The routine will also draw a box, axes, and numeric labels if requested.

For greater control over the size of the plots, axis labelling and tick intervals, more complex graphs should make use of the functions plvpor, plvasp, plvpas, plwind, plbox, and routines for manipulating axis labelling plgxax through plszax.