Contents of Example 2:

Example 2:

Now we will embellish the plot a little with some labels. This input file produces Figure

    set terminal latex
    set output "eg2.tex"
    set size 5/5., 4/3.
    set format xy "$%g$"
    set title "This is a plot of $y=sin(x)$"
    set xlabel "This is the $x$ axis"
    set ylabel "This is\\the\\$y$ axis"
    plot [0:6.28] [0:1] sin(x)

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$\begin{center}\vbox{\input{eg2} }\end{center}$

We have specified the plot to be 5 inches wide and 4 inches tall with the set size command. This is the size of the area used by the plot, including space for the labels. In the first example, this size was the default 5 inches by 3 inches. By specifying the scaling factors of 1 (or 5/5) and 1.3333 (or 4/3), we obtain the desired plot size.

We have requested that the format used by the x- and y-axis tic mark labels be in L^ATEX math mode. This makes the labels look a little better. The default is set format xy "%g". The %g represents the general-purpose floating point formatting specification for the printf function in C. Any valid floating-point formatting specification, or L^ATEX command, is allowed in the format.

A title for the plot and labels for the axes were set up in the next three commands. Note that they are processed by L^ATEX and so may have math mode and other symbols in them. The ylabel may have multiple lines, delineated with \\. The ylabel can be moved around with optional offset parameters (see set ylabel in the GNUPLOT manual). Typically, the ylabel needs to be moved to the left to avoid interfering with the left-hand side of the plot. Once these labels are set up, they will be used for all subsequent plot commands until they are changed. These labels are also supported by the other terminal types, but (of course) any L^ATEX code in the string will not be interpreted. We have also defined the range of both x (now [0, 2π]) and y (here [0, 1]).

So far we have plotted one curve, y = sin(x), on one plot. In GNUPLOT, each plot command generates a new plot. If the output is to a screen, the screen is cleared. If to a printer, a new page is produced. In the latex case, a new picture is started. It is not likely that L^ATEX users will want this to happen, so generally each plot has its own input file and is kept in a separate output (.tex) file for inclusion at different places in the document.