Line Graphs

Download and Load Data

download.file("http://www.openintro.org/stat/data/ames.csv", destfile = "ames.csv")
data <- read.csv("/Users/majerus/Downloads/ames.csv")   # update to file path on your computer 

Calculate Mean Sale Price by Year

# This calculation requires the 'plyr' package
if( !is.element("plyr", installed.packages()[,1]) )
  install.packages("plyr")

library(plyr)

mean <- ddply(data, .(Yr.Sold), summarize,     
               mean_price = mean(SalePrice))

Create Line Grap using Base R Commands

plot(mean$Yr.Sold, mean$mean_price, type = "o")

Add Additional Elements to Base Line Graph

plot(mean$Yr.Sold, mean$mean_price, type = "o",
     xlab = "Year", ylab = "Mean Sale Price",  main = "Line Graph of Mean Home Sale Price in Ames, IA", pch = 16, 
     col = "dark blue", lwd = 3, cex = 2) 

Using ggplot2 to Make a Line Graph

# This demo requires the 'ggplot' package
if( !is.element("ggplot2", installed.packages()[,1]) )
  install.packages("ggplot2")

suppressPackageStartupMessages(library(ggplot2))

ggplot(mean, aes(Yr.Sold, mean_price)) + 
  geom_line()

Apply Theme to Line Graph

if( !is.element("ggthemes", installed.packages()[,1]) )
  install.packages("ggthemes")

if( !is.element("scales", installed.packages()[,1]) )
  install.packages("scales")

suppressPackageStartupMessages(library(ggthemes))
suppressPackageStartupMessages(library(scales))

ggplot(mean, aes(Yr.Sold, mean_price)) + 
  geom_line() +
  theme_tufte()

Add Additional Elements to Line Graph

ggplot(mean, aes(Yr.Sold, mean_price)) + 
  geom_line(color="dark blue", size=2) +
  scale_y_continuous("Mean Sale Price", labels = dollar) +
  scale_x_continuous("Year") +
  ggtitle("Mean Home Sale Price in Ames, IA") +
  theme_tufte() +
  theme(plot.title = element_text(size = 16, face="bold"))

Make Your Line Graph Interactive with googleVis

## This demo requires the 'googleVis' package 
if( !is.element("googleVis", installed.packages()[,1]) )
  install.packages("googleVis")

suppressPackageStartupMessages(library(googleVis))
suppressPackageStartupMessages(library(scales))

# add names to new data frame as factor 
mean$pop.html.tooltip=dollar_format()(mean$mean_price)

# create interactive scatter plot using googleVis
line <- gvisScatterChart(mean,                                                           
                         options=list(tooltip="{isHtml:'True'}",
                         legend="none", lineWidth=5, pointSize=3,                                                     
                         vAxis="{title:'Mean Sale Price'}",                         
                         hAxis="{title:'Year'}",                     
                         width=750, height=500))                            

# plot interactive scatter (use 'plot(Hist)' to view in RStudio)
print(line, 'chart') 

Add an Edit Button to Your Line Graph

## This demo requires the 'googleVis' package 
if( !is.element("googleVis", installed.packages()[,1]) )
  install.packages("googleVis")

suppressPackageStartupMessages(library(googleVis))

# create interactive histogram plot using googleVis
line2 <- gvisScatterChart(mean,                                                           
                          options=list(tooltip="{isHtml:'True'}",
                          legend="none", lineWidth=5, pointSize=3,                                                     
                          vAxis="{title:'Mean Sale Price'}",                         
                          hAxis="{title:'Year'}",                     
                          width=750, height=500, 
                          gvis.editor="Edit Graph"))                  

# plot interactive scatter (use 'plot(Hist)' to view in RStudio)
print(line2, 'chart')