Chapter 16 – Using Base Graphics

 
# Chapter 16 - Using Base Graphics
 
# Creating Different Types of Plots
 
 
## Getting an overview of plot
 
large.islands <- head(sort(islands, decreasing=TRUE), 10)
 
plot(large.islands, main="Land area of continents and islands",
   ylab="Land area in square miles")
text(large.islands, labels=names(large.islands), adj=c(0.5, 1))
 
 
## Adding points and lines to a plot
 
plot(faithful)
 
## Adding points
 
short.eruptions <- with(faithful, faithful[eruptions < 3, ])
 
plot(faithful)
points(short.eruptions, col="red", pch=19)
 
## Changing the shape of points
 
## Changing the color
 
head(colors(), 10)
 
## Adding lines to a plot
 
fit <- lm(waiting~eruptions, data=faithful)
 
plot(faithful)
lines(faithful$eruptions, fitted(fit), col="blue")
abline(v=3, col="purple")
 
abline(h=mean(faithful$waiting))
abline(a=coef(fit)[1], b=coef(fit)[2])
abline(fit, col = "red")
 
# Different plot types
 
plot(LakeHuron, type="l", main='type="l"')
plot(LakeHuron, type="p", main='type=p"')
plot(LakeHuron, type="b", main='type="b"')
 
 
x <- seq(0.5, 1.5, 0.25)
y <- rep(1, length(x))
plot(x, y, type="n")
points(x, y)
 
with(mtcars, plot(mpg, disp))
with(mtcars, boxplot(disp, mpg))
with(mtcars, hist(mpg))
 
# Controlling Plot Options and Arguments
 
## Adding titles and axis labels
 
plot(faithful,
   main = "Eruptions of Old Faithful",
   xlab = "Eruption time (min)",
   ylab = "Waiting time to next eruption (min)")
 
 
## Changing plot options
 
### The axes label style
 
plot(faithful, las=1)
 
### The box type
 
plot(faithful, bty="n")
 
### More than one option
 
plot(faithful, las=1, bty="l", col="red", pch=19)
 
### Font size of text and axes
 
x <- seq(0.5, 1.5, 0.25)
y <- rep(1, length(x))
plot(x, y, main="Effect of cex on text size")
text(x, y+0.1, labels=x, cex=x)
 
plot(x, y, main="Effect of cex.main, cex.lab and cex.axis",
  cex.main=1.25, cex.lab=1.5, cex.axis=0.75)
 
## Putting multiple plots on a single page
 
old.par <- par(mfrow=c(1, 2))
plot(faithful, main="Faithful eruptions")
plot(large.islands, main="Islands", ylab="Area")
par(old.par)
 
 
# Saving Graphics to Image Files
 
setwd("~/")
getwd()
png(filename="faithful.png")
plot(faithful)
dev.off()

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