contourLines {grDevices} | R Documentation |
Calculate contour lines for a given set of data.
contourLines(x = seq(0, 1, len = nrow(z)), y = seq(0, 1, len = ncol(z)), z, nlevels = 10, levels = pretty(range(z, na.rm=TRUE), nlevels))
x,y |
locations of grid lines at which the values in z are
measured. These must be in ascending order. By default, equally
spaced values from 0 to 1 are used. If x is a list ,
its components x$x and x$y are used for x
and y , respectively. If the list has component z this
is used for z . |
z |
a matrix containing the values to be plotted (NA s are
allowed). Note that x can be used instead of z for
convenience. |
nlevels |
number of contour levels desired iff
levels is not supplied. |
levels |
numeric vector of levels at which to draw contour lines. |
contourLines
draws nothing, but returns a set of contour lines.
There is currently no documentation about the algorithm. The source code is in ‘$R_HOME/src/main/plot3d.c’.
A list of contours. Each contour is a list with elements:
level |
The contour level. |
x |
The x-coordinates of the contour. |
y |
The y-coordinates of the contour. |
x <- 10*1:nrow(volcano) y <- 10*1:ncol(volcano) contourLines(x, y, volcano)