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% File src/library/graphics/man/image.Rd
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% File src/library/graphics/man/image.Rd
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% Part of the R package, https://www.R-project.org
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% Part of the R package, https://www.R-project.org
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% Copyright 1995-2017 R Core Team
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% Copyright 1995-2019 R Core Team
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% Distributed under GPL 2 or later
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% Distributed under GPL 2 or later
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\name{image}
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\name{image}
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\alias{image}
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\alias{image}
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\alias{image.default}
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\alias{image.default}
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\title{Display a Color Image}
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\title{Display a Color Image}
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\usage{
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\usage{
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image(x, \dots)
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image(x, \dots)
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\method{image}{default}(x, y, z, zlim, xlim, ylim,
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\method{image}{default}(x, y, z, zlim, xlim, ylim,
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col = hcl.colors(12, "YlOrRd"),
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col = hcl.colors(12, "YlOrRd", rev = TRUE),
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add = FALSE, xaxs = "i", yaxs = "i", xlab, ylab,
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add = FALSE, xaxs = "i", yaxs = "i", xlab, ylab,
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breaks, oldstyle = FALSE, useRaster, \dots)
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breaks, oldstyle = FALSE, useRaster, \dots)
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}
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}
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\arguments{
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\arguments{
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\item{x, y}{locations of grid lines at which the values in \code{z} are
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\item{x, y}{locations of grid lines at which the values in \code{z} are
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intervals cover the range, so that values just outside the range
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intervals cover the range, so that values just outside the range
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will be plotted.}
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will be plotted.}
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\item{xlim, ylim}{ranges for the plotted \code{x} and \code{y} values,
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\item{xlim, ylim}{ranges for the plotted \code{x} and \code{y} values,
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defaulting to the ranges of \code{x} and \code{y}.}
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defaulting to the ranges of \code{x} and \code{y}.}
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\item{col}{a list of colors such as that generated by
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\item{col}{a list of colors such as that generated by
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\code{\link{rainbow}}, \code{\link{heat.colors}},
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\code{\link{topo.colors}}, \code{\link{terrain.colors}} or similar
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\code{\link{hcl.colors}}, \code{\link{gray.colors}} or similar
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functions.}
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functions.}
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\item{add}{logical; if \code{TRUE}, add to current plot (and disregard
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\item{add}{logical; if \code{TRUE}, add to current plot (and disregard
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the following four arguments). This is rarely useful because
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the following four arguments). This is rarely useful because
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\code{image} \sQuote{paints} over existing graphics.}
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\code{image} \sQuote{paints} over existing graphics.}
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\item{xaxs, yaxs}{style of x and y axis. The default \code{"i"} is
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\item{xaxs, yaxs}{style of x and y axis. The default \code{"i"} is
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Creates a grid of colored or gray-scale rectangles with colors
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Creates a grid of colored or gray-scale rectangles with colors
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corresponding to the values in \code{z}. This can be used to display
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corresponding to the values in \code{z}. This can be used to display
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three-dimensional or spatial data aka \emph{images}.
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three-dimensional or spatial data aka \emph{images}.
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This is a generic function.
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This is a generic function.
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The functions \code{\link{hcl.colors}}, \code{\link{terrain.colors}}
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The function \code{\link{hcl.colors}} provides a broad range of sequential
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and \code{\link{topo.colors}} create heat-spectrum (red to white) and
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topographical color schemes suitable for displaying ordered data, with
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color palettes that are suitable for displaying ordered data, with
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\code{n} giving the number of colors desired.
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\code{n} giving the number of colors desired.
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}
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}
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\details{
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\details{
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The length of \code{x} should be equal to the \code{nrow(z)+1} or
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The length of \code{x} should be equal to the \code{nrow(z)+1} or
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\code{nrow(z)}. In the first case \code{x} specifies the boundaries
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\code{nrow(z)}. In the first case \code{x} specifies the boundaries
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look nicer (but are less modular),
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look nicer (but are less modular),
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\code{\link{contour}};
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\code{\link{contour}};
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The \CRANpkg{lattice} equivalent of \code{image} is
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The \CRANpkg{lattice} equivalent of \code{image} is
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\code{\link[lattice]{levelplot}}.
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\code{\link[lattice]{levelplot}}.
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\code{\link{heat.colors}}, \code{\link{topo.colors}},
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\code{\link{hcl.colors}}, \code{\link{gray.colors}},
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\code{\link{terrain.colors}}, \code{\link{rainbow}},
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\code{\link{hsv}}, \code{\link{par}}.
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\code{\link{hcl}}, \code{\link{hsv}}, \code{\link{par}}.
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\code{\link{dev.capabilities}} to see if \code{useRaster = TRUE} is
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\code{\link{dev.capabilities}} to see if \code{useRaster = TRUE} is
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supported on the current device.
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supported on the current device.
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}
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}
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\examples{
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\examples{
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require(grDevices) # for colours
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require("grDevices") # for colours
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x <- y <- seq(-4*pi, 4*pi, len = 27)
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x <- y <- seq(-4*pi, 4*pi, length.out = 27)
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r <- sqrt(outer(x^2, y^2, "+"))
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r <- sqrt(outer(x^2, y^2, "+"))
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image(z = z <- cos(r^2)*exp(-r/6), col = gray((0:32)/32))
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image(z = z <- cos(r^2)*exp(-r/6), col = gray.colors(33))
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image(z, axes = FALSE, main = "Math can be beautiful ...",
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image(z, axes = FALSE, main = "Math can be beautiful ...",
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xlab = expression(cos(r^2) * e^{-r/6}))
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xlab = expression(cos(r^2) * e^{-r/6}))
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contour(z, add = TRUE, drawlabels = FALSE)
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contour(z, add = TRUE, drawlabels = FALSE)
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# Volcano data visualized as matrix. Need to transpose and flip
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# Volcano data visualized as matrix. Need to transpose and flip
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image(t(volcano)[ncol(volcano):1,])
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image(t(volcano)[ncol(volcano):1,])
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# A prettier display of the volcano
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# A prettier display of the volcano
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x <- 10*(1:nrow(volcano))
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x <- 10*(1:nrow(volcano))
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y <- 10*(1:ncol(volcano))
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y <- 10*(1:ncol(volcano))
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image(x, y, volcano, col = terrain.colors(100), axes = FALSE)
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image(x, y, volcano, col = hcl.colors(100, "terrain"), axes = FALSE)
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contour(x, y, volcano, levels = seq(90, 200, by = 5),
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contour(x, y, volcano, levels = seq(90, 200, by = 5),
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add = TRUE, col = "peru")
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add = TRUE, col = "brown")
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axis(1, at = seq(100, 800, by = 100))
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axis(1, at = seq(100, 800, by = 100))
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axis(2, at = seq(100, 600, by = 100))
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axis(2, at = seq(100, 600, by = 100))
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box()
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box()
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title(main = "Maunga Whau Volcano", font.main = 4)
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title(main = "Maunga Whau Volcano", font.main = 4)
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}
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}
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