#### Overview of this book

gnuplot is the world's finest technical plotting software, used by scientists, engineers, and others for many years. It is in constant development and runs on practically every operating system, and can produce output in almost any format. The quality of its 3d plots is unmatched and its ability to be incorporated into computer programs and document preparation systems is excellent. gnuplot Cookbook ñ it will help you master gnuplot. Start using gnuplot immediately to solve your problems in data analysis and presentation. Quickly find a visual example of the graph you want to make and see a complete, working script for producing it. Learn how to use the new features in gnuplot 4.4. Find clearly explained, working examples of using gnuplot with LaTeX and with your own computer programming language. You will master all the ins and outs of gnuplot through gnuplot Cookbook. You will learn to plot basic 2d to complex 3d plots, annotate from simple labels to equations, integrate from simple scripts to full documents and computer progams. You will be taught to annotate graphs with equations and symbols that match the style of the rest of your text, thus creating a seamless, professional document. You will be guided to create a web page with an interactive graph, and add graphical output to your simulation or numerical analysis program. Start using all of gnuplot's simple to complex features to suit your needs, without studying its 200 page manual through this Cookbook.
gnuplot Cookbook
Credits
www.PacktPub.com
Preface
Free Chapter
Plotting Curves, Boxes, Points, and more
Annotating with Labels and Legends
Applying Colors and Styles
Combining Multiple Plots
Programming gnuplot and Dealing with Data
The Third Dimension
Using and Making Graphical User Interfaces
Surveying Special Topics
Finding Help and Information
Index

## Plotting a path in 3D

Back in Chapter 1, Plotting Curves, Boxes, Points, and more, we used parametric plotting to make graphs of complicated 2D paths. We can do the same thing in 3D to draw a complex curve in space.

This might be thought of as a 3D Lissajous figure. The path intersects itself at several places.

### How to do it…

Following is the code for the previous figure:

```set samp 100
set xtics .4
set ytics .4
set parametric
set urange [-pi:pi]
set ztics 1
splot cos(u),sin(3*u),cos(5*u) lw 2```

Note that the appearance of the plot will change radically depending on the viewpoint.

### How it works…

In exploring parametric plotting in 2D in Chapter 1, Plotting Curves, Boxes, Points, and more, we learned that the `x` and `y` independent variables were replaced by the single parameter `t`, and we had to specify two functions separated by commas; the first gave the x coordinate and the second gave the y coordinate that were plotted simultaneously as `t` was varied between the limits defined in the `trange`.

To plot a...