PGPLOT is a Fortran subroutine package for drawing simple scientific
graphs on various graphics display devices. It was originally developed
for use with astronomical data reduction programs in the Caltech
Astronomy Department.

It consists of a library of routines that are Fortran- and C-callable.
There are routines that are device-dependent, in that they can produce
output for various terminals, image displays, dot-matrix printers,
laser printers, and pen plotters. Common file formats supported include
PostScript and GIF.

PGPLOT is not public-domain software. However, it is freely available
for non-commercial use. The source code and documentation are
copyrighted by California Institute of Technology, and may not be
redistributed or placed on public Web servers without permission. The
software is provided "as is" with no warranty.