In statcourses/BristolVis: Data visualisation and web applications course

knitr::opts_chunk$set(echo = TRUE, eval = TRUE, warning=FALSE, message=FALSE, fig.width=7)

Instructions

Please note: The graphs shown at each question is only a suggested plot for the solution. You may want to reproduce it or create a diiferent plot to answer the corresponding question.

Getting started

To get you familiar with the underlying ggplot2 concepts, we'll recreate some standard graphics. Some of these plots aren't particularly useful, we are just using them for illustration purposes.

To begin with, load the ggplot2

library("ggplot2")

Next we load the movies data set

# Details of the movies dataset can be displayed by:
library(ggplot2movies)
data(movies, package="ggplot2movies")
?movies

When loading in data, it's a good idea to check some basic characteristics:

str(movies)
dim(movies)
names(movies)
head(movies)

Plot some information

Feel free to experiment with your own ideas. I present some graphs as a reference that you may try to reproduce if you wish.

1. What is the number of movies produced per year?

g = ggplot(data=movies, aes(x=year))
g1 = g + geom_histogram(binwidth = 1, fill="#2b8cbe", alpha=0.6) +
  xlab("Year") + ylab("Number of movies produced")

g1

2. What is the number of movies produced per year per genre (action, animation ect)?

# TIP: You need first to create a genre variable:
genre <- rep(0, nrow(movies))
for(i in 18:24)
{
  genre[movies[,i]==1] <- names(movies)[i]
}; genre[genre==0] <- "Unknown"
movies$Genre <- genre

# define a vector for colors to be used in the plot
clr <- c('#8dd3c7','#ffffb3','#bebada','#fb8072','#80b1d3','#fdb462','#b3de69', '#000000')

ggplot(movies, aes(x=year, fill=Genre)) + geom_histogram(binwidth=1) + scale_fill_manual(values = clr) +
  xlab("Year") + ylab("Number of movies produced") + ylim(0,1900) + xlim(1890,2005)

3. Create a graph to present information on the rating of movies.

ggplot(movies, aes(x=rating)) + geom_density(fill="#2b8cbe", alpha=0.6) + 
  ylab("Density of Movie Rating") + xlab("Score (out of 10)")

4. Is there a difference on rating depending on genre?

ggplot(movies, aes(x=factor(Genre), y=rating)) + xlab("") + ylab("Rating (out of 10") +
  geom_violin(fill="red", alpha=0.4) +
  stat_summary(fun.y = median, geom='point')

5. Is the rating influenced by the number of votes?

ggplot(movies, aes(x=votes, y=rating)) + xlab("Votes") + ylab("Rating") +
  stat_binhex() +
  scale_fill_gradient(low="lightblue", high="red", breaks=c(0, 1500, 3000, 5000),
                      limits=c(0, 5000))