special linetypes

A few special (non-numerical) linetypes are recognized.

lt black specifies a solid black line.

lt bgnd specifies a solid line with the background color of the current terminal. See background.

lt nodraw skips drawing the line altogether. This is useful in conjunction with plot style linespoints. It allows you to suppress the line component of the plot while retaining point properties that are available only in this plot style. For example

     plot f(x) with linespoints lt nodraw pointinterval -3

will draw only every third point and will isolate it by placing a small circle of background color underneath it. See linespoints. lt nodraw may also be used to suppress a particular set of lines that would otherwise be drawn automatically. For example you could suppress certain contour levels in a contour plot by setting their linetype to nodraw.