    # Example 13 -- TS diagram, with isopycnals

    # Draw Axes
    set line width axis 0.25
    set line width 0.75
    .tic_size. = 0.1		# cm
    set symbol size 0.03
    .isopycnal_fontsize. = 8	# for isopycnal labels
    .axes_fontsize. = 10		# for axes
    set font size .axes_fontsize.
    set x margin 2
    set x size 10
    set y margin 2
    set y size 10
    set tic size .tic_size.
    set x name "Salinity / PSU"
    set y name "Potential Temperature / $\circ$C"
    set x axis 34 35 0.5 0.1
    set y axis 2 10 1
    set axes style offset
    draw axes 1
    set clip on
    .old. = ..fontsize..
    set font size .isopycnal_fontsize.
    set line width rapidograph 1
    draw isopycnal            26.00
    draw isopycnal            27.00
    draw isopycnal            28.00
    draw isopycnal            29.00
    set line width rapidograph 3x0
    draw isopycnal unlabelled 26.75
    draw isopycnal unlabelled 26.50
    draw isopycnal unlabelled 26.25
    draw isopycnal unlabelled 27.75
    draw isopycnal unlabelled 27.50
    draw isopycnal unlabelled 27.25
    draw isopycnal unlabelled 28.75
    draw isopycnal unlabelled 28.50
    draw isopycnal unlabelled 28.25
    set clip off
    set font size .old.
    #
    # Draw the data.
    open example13.dat
    read columns x y
    set color blue
    set symbol size 0.1
    draw symbol bullet
    set font size 14
    set color black
    draw title "Example 13 -- TS diagram, with isopycnals"