5 作図
Rの得意な作業のひとつが作図です。
5.1 どんな図を作成できるのか
Rには最初から関数やパッケージの使用例があります。
##
## plot> Speed <- cars$speed
##
## plot> Distance <- cars$dist
##
## plot> plot(Speed, Distance, panel.first = grid(8, 8),
## plot+ pch = 0, cex = 1.2, col = "blue")
##
## plot> plot(Speed, Distance,
## plot+ panel.first = lines(stats::lowess(Speed, Distance), lty = "dashed"),
## plot+ pch = 0, cex = 1.2, col = "blue")
##
## plot> ## Show the different plot types
## plot> x <- 0:12
##
## plot> y <- sin(pi/5 * x)
##
## plot> op <- par(mfrow = c(3,3), mar = .1+ c(2,2,3,1))
##
## plot> for (tp in c("p","l","b", "c","o","h", "s","S","n")) {
## plot+ plot(y ~ x, type = tp, main = paste0("plot(*, type = \"", tp, "\")"))
## plot+ if(tp == "S") {
## plot+ lines(x, y, type = "s", col = "red", lty = 2)
## plot+ mtext("lines(*, type = \"s\", ...)", col = "red", cex = 0.8)
## plot+ }
## plot+ }
##
## plot> par(op)
##
## plot> ##--- Log-Log Plot with custom axes
## plot> lx <- seq(1, 5, length.out = 41)
##
## plot> yl <- expression(e^{-frac(1,2) * {log[10](x)}^2})
##
## plot> y <- exp(-.5*lx^2)
##
## plot> op <- par(mfrow = c(2,1), mar = par("mar")-c(1,0,2,0), mgp = c(2, .7, 0))
##
## plot> plot(10^lx, y, log = "xy", type = "l", col = "purple",
## plot+ main = "Log-Log plot", ylab = yl, xlab = "x")##
## plot> plot(10^lx, y, log = "xy", type = "o", pch = ".", col = "forestgreen",
## plot+ main = "Log-Log plot with custom axes", ylab = yl, xlab = "x",
## plot+ axes = FALSE, frame.plot = TRUE)
##
## plot> my.at <- 10^(1:5)
##
## plot> axis(1, at = my.at, labels = formatC(my.at, format = "fg"))
##
## plot> e.y <- -5:-1 ; at.y <- 10^e.y
##
## plot> axis(2, at = at.y, col.axis = "red", las = 1,
## plot+ labels = as.expression(lapply(e.y, function(E) bquote(10^.(E)))))
##
## plot> par(op)Enterキー または Returnキー を押すと次々と図が表示されます。
同時に，コンソールには，作図に用いたコードが表示されます。
##
##
## demo(graphics)
## ---- ~~~~~~~~
##
## > # Copyright (C) 1997-2009 The R Core Team
## >
## > require(datasets)
##
## > require(grDevices); require(graphics)
##
## > ## Here is some code which illustrates some of the differences between
## > ## R and S graphics capabilities. Note that colors are generally specified
## > ## by a character string name (taken from the X11 rgb.txt file) and that line
## > ## textures are given similarly. The parameter "bg" sets the background
## > ## parameter for the plot and there is also an "fg" parameter which sets
## > ## the foreground color.
## >
## >
## > x <- stats::rnorm(50)
##
## > opar <- par(bg = "white")
##
## > plot(x, ann = FALSE, type = "n")
##
## > abline(h = 0, col = gray(.90))
##
## > lines(x, col = "green4", lty = "dotted")
##
## > points(x, bg = "limegreen", pch = 21)
##
## > title(main = "Simple Use of Color In a Plot",
## + xlab = "Just a Whisper of a Label",
## + col.main = "blue", col.lab = gray(.8),
## + cex.main = 1.2, cex.lab = 1.0, font.main = 4, font.lab = 3)
##
## > ## A little color wheel. This code just plots equally spaced hues in
## > ## a pie chart. If you have a cheap SVGA monitor (like me) you will
## > ## probably find that numerically equispaced does not mean visually
## > ## equispaced. On my display at home, these colors tend to cluster at
## > ## the RGB primaries. On the other hand on the SGI Indy at work the
## > ## effect is near perfect.
## >
## > par(bg = "gray")
##
## > pie(rep(1,24), col = rainbow(24), radius = 0.9)
##
## > title(main = "A Sample Color Wheel", cex.main = 1.4, font.main = 3)
##
## > title(xlab = "(Use this as a test of monitor linearity)",
## + cex.lab = 0.8, font.lab = 3)
##
## > ## We have already confessed to having these. This is just showing off X11
## > ## color names (and the example (from the postscript manual) is pretty "cute".
## >
## > pie.sales <- c(0.12, 0.3, 0.26, 0.16, 0.04, 0.12)
##
## > names(pie.sales) <- c("Blueberry", "Cherry",
## + "Apple", "Boston Cream", "Other", "Vanilla Cream")
##
## > pie(pie.sales,
## + col = c("purple","violetred1","green3","cornsilk","cyan","white"))
##
## > title(main = "January Pie Sales", cex.main = 1.8, font.main = 1)
##
## > title(xlab = "(Don't try this at home kids)", cex.lab = 0.8, font.lab = 3)
##
## > ## Boxplots: I couldn't resist the capability for filling the "box".
## > ## The use of color seems like a useful addition, it focuses attention
## > ## on the central bulk of the data.
## >
## > par(bg="cornsilk")
##
## > n <- 10
##
## > g <- gl(n, 100, n*100)
##
## > x <- rnorm(n*100) + sqrt(as.numeric(g))
##
## > boxplot(split(x,g), col="lavender", notch=TRUE)
##
## > title(main="Notched Boxplots", xlab="Group", font.main=4, font.lab=1)
##
## > ## An example showing how to fill between curves.
## >
## > par(bg="white")
##
## > n <- 100
##
## > x <- c(0,cumsum(rnorm(n)))
##
## > y <- c(0,cumsum(rnorm(n)))
##
## > xx <- c(0:n, n:0)
##
## > yy <- c(x, rev(y))
##
## > plot(xx, yy, type="n", xlab="Time", ylab="Distance")
##
## > polygon(xx, yy, col="gray")
##
## > title("Distance Between Brownian Motions")
##
## > ## Colored plot margins, axis labels and titles. You do need to be
## > ## careful with these kinds of effects. It's easy to go completely
## > ## over the top and you can end up with your lunch all over the keyboard.
## > ## On the other hand, my market research clients love it.
## >
## > x <- c(0.00, 0.40, 0.86, 0.85, 0.69, 0.48, 0.54, 1.09, 1.11, 1.73, 2.05, 2.02)
##
## > par(bg="lightgray")
##
## > plot(x, type="n", axes=FALSE, ann=FALSE)
##
## > usr <- par("usr")
##
## > rect(usr[1], usr[3], usr[2], usr[4], col="cornsilk", border="black")
##
## > lines(x, col="blue")
##
## > points(x, pch=21, bg="lightcyan", cex=1.25)
##
## > axis(2, col.axis="blue", las=1)
##
## > axis(1, at=1:12, lab=month.abb, col.axis="blue")
##
## > box()
##
## > title(main= "The Level of Interest in R", font.main=4, col.main="red")
##
## > title(xlab= "1996", col.lab="red")
##
## > ## A filled histogram, showing how to change the font used for the
## > ## main title without changing the other annotation.
## >
## > par(bg="cornsilk")
##
## > x <- rnorm(1000)
##
## > hist(x, xlim=range(-4, 4, x), col="lavender", main="")
##
## > title(main="1000 Normal Random Variates", font.main=3)
##
## > ## A scatterplot matrix
## > ## The good old Iris data (yet again)
## >
## > pairs(iris[1:4], main="Edgar Anderson's Iris Data", font.main=4, pch=19)
##
## > pairs(iris[1:4], main="Edgar Anderson's Iris Data", pch=21,
## + bg = c("red", "green3", "blue")[unclass(iris$Species)])
##
## > ## Contour plotting
## > ## This produces a topographic map of one of Auckland's many volcanic "peaks".
## >
## > x <- 10*1:nrow(volcano)
##
## > y <- 10*1:ncol(volcano)
##
## > lev <- pretty(range(volcano), 10)
##
## > par(bg = "lightcyan")
##
## > pin <- par("pin")
##
## > xdelta <- diff(range(x))
##
## > ydelta <- diff(range(y))
##
## > xscale <- pin[1]/xdelta
##
## > yscale <- pin[2]/ydelta
##
## > scale <- min(xscale, yscale)
##
## > xadd <- 0.5*(pin[1]/scale - xdelta)
##
## > yadd <- 0.5*(pin[2]/scale - ydelta)
##
## > plot(numeric(0), numeric(0),
## + xlim = range(x)+c(-1,1)*xadd, ylim = range(y)+c(-1,1)*yadd,
## + type = "n", ann = FALSE)
##
## > usr <- par("usr")
##
## > rect(usr[1], usr[3], usr[2], usr[4], col="green3")
##
## > contour(x, y, volcano, levels = lev, col="yellow", lty="solid", add=TRUE)
##
## > box()
##
## > title("A Topographic Map of Maunga Whau", font= 4)
##
## > title(xlab = "Meters North", ylab = "Meters West", font= 3)
##
## > mtext("10 Meter Contour Spacing", side=3, line=0.35, outer=FALSE,
## + at = mean(par("usr")[1:2]), cex=0.7, font=3)
##
## > ## Conditioning plots
## >
## > par(bg="cornsilk")
##
## > coplot(lat ~ long | depth, data = quakes, pch = 21, bg = "green3")
##
## > par(opar)##
##
## demo(image)
## ---- ~~~~~
##
## > # Copyright (C) 1997-2009 The R Core Team
## >
## > require(datasets)
##
## > require(grDevices); require(graphics)
##
## > x <- 10*(1:nrow(volcano)); x.at <- seq(100, 800, by=100)
##
## > y <- 10*(1:ncol(volcano)); y.at <- seq(100, 600, by=100)
##
## > # Using Terrain Colors
## >
## > image(x, y, volcano, col=terrain.colors(100),axes=FALSE)
##
## > contour(x, y, volcano, levels=seq(90, 200, by=5), add=TRUE, col="brown")
##
## > axis(1, at=x.at)
##
## > axis(2, at=y.at)
##
## > box()
##
## > title(main="Maunga Whau Volcano", sub = "col=terrain.colors(100)", font.main=4)
##
## > # Using Heat Colors
## >
## > image(x, y, volcano, col=heat.colors(100), axes=FALSE)
##
## > contour(x, y, volcano, levels=seq(90, 200, by=5), add=TRUE, col="brown")
##
## > axis(1, at=x.at)
##
## > axis(2, at=y.at)
##
## > box()
##
## > title(main="Maunga Whau Volcano", sub = "col=heat.colors(100)", font.main=4)
##
## > # Using Gray Scale
## >
## > image(x, y, volcano, col=gray(100:200/200), axes=FALSE)
##
## > contour(x, y, volcano, levels=seq(90, 200, by=5), add=TRUE, col="black")
##
## > axis(1, at=x.at)
##
## > axis(2, at=y.at)
##
## > box()
##
## > title(main="Maunga Whau Volcano \n col=gray(100:200/200)", font.main=4)
##
## > ## Filled Contours are even nicer sometimes :
## > example(filled.contour)
##
## flld.c> require("grDevices") # for colours
##
## flld.c> filled.contour(volcano, asp = 1) # simple
##
## flld.c> x <- 10*1:nrow(volcano)
##
## flld.c> y <- 10*1:ncol(volcano)
##
## flld.c> filled.contour(x, y, volcano,
## flld.c+ color.palette = function(n) hcl.colors(n, "terrain"),
## flld.c+ plot.title = title(main = "The Topography of Maunga Whau",
## flld.c+ xlab = "Meters North", ylab = "Meters West"),
## flld.c+ plot.axes = { axis(1, seq(100, 800, by = 100))
## flld.c+ axis(2, seq(100, 600, by = 100)) },
## flld.c+ key.title = title(main = "Height\n(meters)"),
## flld.c+ key.axes = axis(4, seq(90, 190, by = 10))) # maybe also asp = 1
##
## flld.c> mtext(paste("filled.contour(.) from", R.version.string),
## flld.c+ side = 1, line = 4, adj = 1, cex = .66)
##
## flld.c> # Annotating a filled contour plot
## flld.c> a <- expand.grid(1:20, 1:20)
##
## flld.c> b <- matrix(a[,1] + a[,2], 20)
##
## flld.c> filled.contour(x = 1:20, y = 1:20, z = b,
## flld.c+ plot.axes = { axis(1); axis(2); points(10, 10) })
##
## flld.c> ## Persian Rug Art:
## flld.c> x <- y <- seq(-4*pi, 4*pi, length.out = 27)
##
## flld.c> r <- sqrt(outer(x^2, y^2, `+`))
##
## flld.c> ## "minimal"
## flld.c> filled.contour(cos(r^2)*exp(-r/(2*pi)), axes = FALSE, key.border=NA)
##
## flld.c> ## rather, the key *should* be labeled (but axes still not):
## flld.c> filled.contour(cos(r^2)*exp(-r/(2*pi)), frame.plot = FALSE,
## flld.c+ plot.axes = {})
次のコマンドにより，デモの一覧を見ることができる。