Among the scores of graphic packages available, `gnuplot`

stands out for its power and ease of use. Go to X and type `gnuplot`

, and have two sample data files ready: `2D-data.dat`

(two data per line), and `3D-data.dat`

(three data per line).

Examples of 2-D graphs:

`gnuplot> set title "my first graph" gnuplot> plot '2D-data.dat' gnuplot> plot '2D-data.dat' with linespoints gnuplot> plot '2D-data.dat', sin(x) gnuplot> plot [-5:10] '2D-data.dat'`

Example of 3-D graphs (each `row' of X values is followed by a blank line):

`gnuplot> set parametric ; set hidden3d ; set contour gnuplot> splot '3D-data.dat' using 1:2:3 with linespoints`

A single-column datafile (e.g., a time series) can also be plotted as a 2-D graph:

`gnuplot> plot [-5:15] '2D-data-1col.dat' with linespoints`

or as a 3-D graph (blank lines in the datafile, as above):

`gnuplot> set noparametric ; set hidden3d gnuplot> splot '3D-data-1col.dat' using 1 with linespoints`

To print a graph: if the command to print on your Postscript printer is `lpr -Pps file.ps`

, issue:

`gnuplot> set term post gnuplot> set out '| lpr -Pps' gnuplot> replot`

then type `set term x11`

to restore. Don't get confused---the last print will come out only when you quit `gnuplot`

.

For more info, type `help`

or see the examples in directory `/usr/lib/gnuplot/demos/`

, if you have it.

Next Previous Contents