Syntax:
plot ... with filledcurves [option]
where the option can be one of the following
[closed | {above | below} {x1 | x2 | y | r}[=<a>] | xy=<x>,<y>]
The first variant, closed, treats the curve itself as a closed polygon. This is the default if there are two columns of input data.
The second variant is to fill the area between the curve and a given axis, a horizontal or vertical line, or a point.
filledcurves closed ... just filled closed curve, filledcurves x1 ... x1 axis, filledcurves x2 ... x2 axis, etc for y1 and y2 axes, filledcurves y=42 ... line at y=42, i.e. parallel to x axis, filledcurves xy=10,20 ... point 10,20 of x1,y1 axes (arc-like shape). filledcurves above r=1.5 the area of a polar plot outside radius 1.5
The third variant fills the area between two curves sampled at the same set of x coordinates. It requires three columns of input data (x, y1, y2). This is the default if there are three or more columns of input data. If you have a y value in column 2 and an associated error value in column 3 the area of uncertainty can be represented by shading. See also the similar 3D plot style zerrorfill (p. ).
3 columns: x y yerror
plot $DAT using 1:($2-$3):($2+$3) with filledcurves, \ $DAT using 1:2 smooth mcs with lines
The above and below options apply both to commands of the form
... filledcurves above {x1|x2|y|r}=<val>and to commands of the form
... using 1:2:3 with filledcurves belowIn either case the option limits the filled area to one side of the bounding line or curve.
Notes: Not all terminal types support this plotting mode.
The x= and y= keywords are ignored for 3 columns data plots
Zooming a filled curve drawn from a datafile may produce empty or incorrect areas because gnuplot is clipping points and lines, and not areas.
If the values 4#4x5#5, 4#4y5#5, or 4#4a5#5 are outside the drawing boundary they are
moved to the graph boundary. Then the actual fill area in the case
of option xy=4#4x5#5,4#4y5#5 will depend on xrange and yrange.