Graphics Options

For the examples below, we need to load some data.

pers <- read.csv('https://faculty.ung.edu/rsinn/data/personality.csv')
caff <- pers$Caff

Main Title

The standard titles of various graphics in R can be awkward as demonstrated below.

plot(density(caff))

boxplot(caff)

To change the main title for a graphical display, we use the option main = as shown below.

plot(density(caff), main = 'Density Plot: Daily Caffeine Consumption')

Titles for X-axis and Y-axis

The option xlab controls the \(x\)-axis label while ylab does the same for the \(y\)-axis label.

plot(density(caff),
     main = 'Density Plot: Daily Caffeine Consumption',
     xlab = 'Number of 8 oz Serving Per Day',
     ylab = 'Density')

Line Width

In certain graphics, we can emphasize things by increasing or decreasing line width with lwd parameter. The options available are shown in the graphic below.

For example, let’s use a rather large width for the density plot with lwd = 4.

plot(density(caff), 
     lwd = 4,
     main = 'Density Plot: Daily Caffeine Consumption',
     xlab = 'Number of 8 oz Serving Per Day',
     ylab = 'Density')

Color

The col = parameter allows to identify colors by name as in ‘red’ or by by hexidecimal code as in #FFC00. The simplest method is use color names, as shown below.

plot(density(caff), 
     lwd = 3,
     col = 'blue',
     main = 'Density Plot: Daily Caffeine Consumption',
     xlab = 'Number of 8 oz Serving Per Day',
     ylab = 'Density')

Other Plot Types

R is very consistent in allowing the standard graphical parameters to operate unchanged across a wide variety of different graphics. Some examples are shown below.

age <- pers$Age
boxplot(age, 
        main = "Ages")

hist(age, breaks = 8,
    col = 'red',
    main = 'Histogram: Ages',
    xlab = 'Age in Years')