contourLines

Calculate Contour Lines

Calculate contour lines for a given set of data.

Keywords
dplot
Usage
contourLines(x = seq(0, 1, length.out = nrow(z)), y = seq(0, 1, length.out = ncol(z)), z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels))
Arguments
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 (NAs 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.
Details

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’.

Value

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.

See Also

options("max.contour.segments") for the maximal complexity of a single contour line.

contour.

Aliases
  • contourLines
Examples
library(grDevices) x <- 10*1:nrow(volcano) y <- 10*1:ncol(volcano) contourLines(x, y, volcano)
Documentation reproduced from package grDevices, version 3.1.2, License: Part of R 3.1.2

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