Gluplot is a data plotting package. It was originally intended both as graphical library and as standalone program which would allow scientists and students to visualize data. (The "GLU" in gluplot means that it is OpenGL/GLU/glut based.) Gluplot handles both curves (2D) and surfaces (3D). For 2D plots, there are many plot styles, including lines, points, lines with points, error bars and impulses. Surfaces are plotted as a color map on the x-y plane. Gluplot supplies both linear and logarithmic axes. Moreover, any other axis distortion is available using gluplot library. Axis scale and also many other settings are changeable by gluplot command-line options or by menu items and hot-keys after it runs. After all, gluplot supports high quality plot output to PostScript (PS), Encapsulated PostScript (EPS) and Portable Document Format (PDF) files.
URL: http://ftp.jinr.ru/programs/jinrlib/gluplot/indexe.html
License: GPLv2
gnuplot 4 has always been in Ubuntu.