PGPLOT is a device-independent graphics subroutine library written starting in 1983 by Tim Pearson, a professor at the California Institute of Technology.
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.
[1] 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.
Interactive devices can be used to deliver numeric parameters to the controlling program via a graphics cursor.
The library PG2PLplot has been developed to aid the transition from PGPlot to PLplot in Fortran programs.