Plotting with Gnuplot

Overview

Graphical display is an essential part of visualizing, analysing, and presenting scientific results. We present some basic techniques for turning the output of your program into 2-D and 3-D plots, images, and movies. Specifically, we discuss the gnuplot graphics package, which will allow you to produce high-quality plots with minimal effort, and save them in a form suitable for printing or inclusion in printed documents. A helpful tutorial on gnuplot may be found here; the full (long!) gnuplot manual is here.

Outline

Presenting data
- text and tables
- 2-D graphs
- 3-D graphs of lines or surfaces
- contour plots and more complex combinations
- images and simple movies (or more complex ones)
Some basic requirements for a plotting package
What data format should we use? Exercise: making datafiles.
Introduction to gnuplot
An application from the Graduate workshop: fw.c. Save the output of this program in a file -- fw.dat, say -- then run gnuplot with the command

plot [0:1.5] [0:1.2] "fw.dat"

to see the convergence of the bisection procedure. Or use gnuplot's index feature to see specific iterations:

plot [0:1.5] [0:1.2] "fw.dat" index 5:8
The gpl script