A schizophrenic system plot package

A system plot package is a set of routines that forms plotter machine instructions. Here, system plot routines are assumed to form instructions for relatively low-level plotting tasks such as drawing a line or, at most, drawing an annotated axis, while graphics utility routines are used to perform higher level tasks, such as drawing a contour map, through the use of the lower level routines. System plot packages have certain desirable attributes which are often conflicting or even mutually exclusive. For example, at NCAR almost all plotting is done on a CDC DD80, suggesting that the plot package should be designed to produce instructions for that particular plotter, but the occasional use of other plotters makes device independence essential.