Introduction to GGPLOT2

This guide introduces users to the ggplot2 R package. Ggplot2 is a popular package that is used to make publication quality graphs in R. The official documentation for the ggplot2 package can be found here. It includes descriptions of functions and sample datasets.

This guide consists of 3 data visualization examples. You can download the code used in this guide here.

Once you have gone over these examples and you feel confident about them, you can test your understanding by trying this activity. If you have any questions, you can request for assistance by filling out our support request form here.

Install package

install.packages("ggplot2")
library(ggplot2

Example 1: Histogram of the Price of Diamonds

data(diamonds)
ggplot(diamonds, aes(price)) + geom_histogram()
ggplot(diamonds, aes(price)) + geom_histogram() + theme_classic()
ggplot(diamonds, aes(price)) + geom_histogram(binwidth=100) + theme_classic()
ggplot(diamonds, aes(price)) + 
  geom_histogram(binwidth=100, fill="darkblue", color="lightblue") + 
  theme_classic() + 
  ggtitle("Histogram of the Price of Diamonds") + 
  theme(plot.title=element_text(size=20, hjust=0.5)) + 
  xlab("Price") + ylab("Count")
ggsave("histogram1.png")

Histogram of Price of Diamonds

 

Example 2: Scatterplot of the Price and the Weight of Diamonds

ggplot(diamonds, aes(carat, price)) + geom_point()
ggplot(diamonds, aes(carat, price, colour=clarity)) + 
  geom_point(shape="diamond filled") + 
  theme_light() + 
  ggtitle("Relationship between the Price and the Weight of Diamonds")

install.packages("colourpicker")
myscattercolours <- c("#7FFFD4", "#66CDAA", "#458B74", "#00FFFF", "#1C86EE", "#104E8B", "#8B4500", "#FF7F00")

ggplot(diamonds, aes(carat, price, colour=clarity)) + 
  geom_point(shape="diamond filled") + 
  theme_light() + 
  ggtitle("Relationship between the Price and the Weight of Diamonds") + 
  scale_colour_manual(values=myscattercolours) +
  xlab("Carat") + ylab("Price") + 
  guides(colour=guide_legend("Clarity"))

Scatterplot of the Price and the Weight of Diamonds

 

Example 3: Time Series of Median Unemployment Duration in Weeks

data(economics)
ggplot(economics, aes(x=date, y=uempmed)) +
  theme_minimal() +
  geom_line(colour="yellow3", linewidth=1) + 
  labs(title="US Economic Time Series",
       subtitle="Median Unemployment Duration vs Month of Data Collection") +
  xlab("Month of Data Collection") +
  ylab("Median Unemployment Duration in Weeks")

Time Series of Median Unemployment Duration in Weeks

 

Resources

1. GGPLOT2 Documentation: https://cran.r-project.org/web/packages/ggplot2/ggplot2.pdf
2. GGPLOT2 Tidyverse Reference: https://ggplot2.tidyverse.org/reference/
3. Additional code here.

 

Technique: Data Visualization | Tools: R
Date Created: Updated: