Gnuplot
From NA-Wiki
Gnuplot makes it very easy to produce nice looking eps plots from the numerical output of your simulation. A good starting points is the following snippet. Either type it in on the gnuplot prompt, or save it in a file and run it from gnuplot with load "file.p".
set terminal postscript enhanced color size 5,4 "Helvetica,10" set out "test.eps" set pointsize 2 set border linewidth 0.5 unset key set title "Some plot" set xlabel "{/Symbol s}" set ylabel "field" plot "data1d.txt" with points, \ "data1d.txt" smooth csplines with lines
This reads the data in data1d.txt and plots it to test.eps. The size is set to 5x4 inches.