GNU plot is very helpful for plotting data and quite powerful too. After some searching I found the book GNU plot in action. I fount this website very useful for surface plots : http://lowrank.net/gnuplot/plot3d2-e.html This is another useful reference : http://www.phyast.pitt.edu/~zov1/gnuplot/html/intro.html This always helps : http://www.gnuplot.info/. Hint: I think …