Department of Engineering

IT Services

Graphical output

Obtaining graphical output is very easy. The basic syntax is plot(x,y) which plots vector y (ordinate) against vector x (abscissa). For example to plot sin(t) against t, using the vectors we have already created, type


The plot appears in a separate graphics window. Now you can add some axis labels and a rectangular grid by using menus or by typing

xlabel('t'), ylabel('sin t'), grid

To get your graph in red rather than black, and with a title, type:

plot(t,sint,'r'), title('Half period sine wave')

To position text onto the graph using cross-hairs the gtext command is available. Type help gtext for more information.

There are many other possibilities for controlling graphical output. You can have log-log or semi-log graphs, 3-D graphs of surfaces, contour plots, you can overlay various graphs on top of each other, control the axis ranges, and so on.

You can obtain hard copy of a graph (in fact, of the current contents of the Graphics Window) by typing print.