ExData_Plotting1/plot4.R at master · tobypatterson/ExData_Plotting1 · GitHub

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####
#
# Author: Toby Patterson
# File: plot4.R
# Date: 7 August 2014
#
# Generates several graphs related to power generation.
# Presumes the file project1_datafile.Rda exists in the same directory.
#
####

# Read in the table data
# Note you may need to run generate_datafile.R if this file does not exist
data_file = 'project1_datafile.Rda'
if ( !file.exists(data_file)) {
  stop('Run generate_datafile.R to create the project working datafile.')
}

# Setup output parameters
canvas_size = 480
png(
  file="plot4.png",
  height=canvas_size,
  width=canvas_size
)

# Setup page for displaying four charts
par(mfrow = c(2, 2))

# Chart 1
plot(
  data$DateTime,
  data$Global_active_power,
  xlab='',
  ylab='Global Active Power',
  type='l'
)

# Chart 2
plot(
  data$DateTime,
  data$Voltage,
  xlab="datetime",
  ylab="Voltage",
  type="l",
)

# Chart 3
plot(
  data$DateTime,
  data$Sub_metering_1,
  xlab='',
  ylab='Energy sub metering',
  type='n'
)

# Plot points
points(data$DateTime,data$Sub_metering_1,col='black',type='l')
points(data$DateTime,data$Sub_metering_2,col='red',type='l')
points(data$DateTime,data$Sub_metering_3,col='blue',type='l')

legend("topright",
  col=c("black", "red", "blue"),
  c("Sub_metering_1", "Sub_metering_2", "Sub_metering_3"),
  lty=1
)

# Chart 4
plot(
  data$DateTime,
  data$Global_reactive_power,
  xlab="datetime",
  ylab="Global_reactive_power",
  type = "l"
)

# Yes I do want this
mtext('generated by Toby Patterson, 7 Sept 2014',1,4,cex=.5)

# Detatch
dev.off()