Cgraph  PostScript plotting library in C 

CGraph is a set of C functions that generate PostScript or Encapsulated PostScript for publication quality scientific plots. Output color or B&W easily. Many different plots scales including loglog. Works with any C compiler. Freeware. (Aug 1999)

Flounder  4D data visualization 

Flounder is a program to quickly visualize 4D data (x,y,z,t). It can produce isosurfaces, solid renderings, as well as 2D slices. Output options include PNG, GIF, and AVI files. Open Source. Unix/Win32 (Apr 2001)

GnuPlot 

Gnuplot is a commandline driven interactive function and data plotting utility for UNIX, MSDOS, and VMS platforms. It supports 2D and 3D plots including curves and sufaces. Includes complete source in C. (Feb 1998)

Guppi  app for graphing and statistical analysis 

Guppi is an easytouse graphical interface for plotting data and performing statistical manipulations. It is a GNOME application, and is available from GNOME CVS. Freeware (Jul 1999)

mathplot  interactive/batch function grapher 

mathplot is a GUI frontend for interactive graphing of functions to XWindows. You can have both equations (y=f(x) or f(x,y)=g(x)) and inequalities Postscript output is available. Freeware. (Jul 1999)

PGPLOT  Graphics Subroutine Library 

PGPLOT is a Fortran or C callable, deviceindependent graphics package for making simple scientific graphs. Supports laser printers, pen plotters, PostScript, and GIF. Supports most Unix and Win32. Freeware for noncommercial use. (Aug 1999)

Books about Graphing   A complete list of books on Graphing available through Amazon.COM 