PGPLOT is a device-independent graphics subroutine library written starting in 1983 by Tim Pearson, a professor at Caltech. PGPLOT is written mostly in FORTRAN with a modular output API that allows output to several dozen types of plotting device. PGPLOT has been widely used in the academic and scientific communities,because it provides both low-level (glyph, point, line, and area) plotting primitives and also high-level facilities for drawing graphs

Graphics

Graphics are visual presentations on some surface, such as a wall, canvas, computer screen, paper, or stone to brand, inform, illustrate, or entertain. Examples are photographs, drawings, Line Art, graphs, diagrams, typography, numbers, symbols, geometric designs, maps, engineering drawings,or...

. PGPLOT is free software

Free software

Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

 in the sense that it may be redistributed to third parties and modified, but only in binary form. Neither the original nor modified source code are allowed to be redistributed. The most recent version of PGPLOT is 5.2.2, released in February 2001, although third parties have written unofficial patches that include support for additional devices, 64 bit systems, and RGB (true color) plotting.

PGPLOT includes device-independent output to many devices including several types of image file, graphics display terminals and plotters, PostScript

PostScript

PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...

 devices, and X Window. Interactive devices can be used to deliver numeric parameters to the controlling program via a graphics cursor

Cursor (computers)

In computing, a cursor is an indicator used to show the position on a computer monitor or other display device that will respond to input from a text input or pointing device. The flashing text cursor may be referred to as a caret in some cases...

. It is known to run on many operating systems, including most Unix-like

Unix-like

A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....

 systems, Mac OS

Mac OS

Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface...

, and Microsoft Windows

Microsoft Windows

Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

.

In part because of its age, PGPLOT has several limitations compared to newer packages such as PLplot

PLplot

PLplot is a library of functions that are often used to make scientific plots in compiled languages such as C, C++, D, Fortran, Ada, OCaml and Java. PLplot can also be used interactively by interpreted languages such as Octave, Python, Perl and Tcl. The current version was written primarily by...

. In particular, PGPLOT supports only 8-bit indexed color graphics, and not full RGB color; and there is no clean way to render graphics directly to an array in program memory.