plot4.r

#--------------------------------
# Coursera - Exploratory Data Analysis
# Project 1 - Plot 4
# Alejandro Fraga
#--------------------------------

# Read Data
setwd("C:/Users/fragaa1/Documents/R-Scripts/Exploratory_Data_Analysis/week1/project")
archive<-"household_power_consumption.txt"
data<-read.table(archive, header=TRUE, sep=";", stringsAsFactors=FALSE, dec=".")
subSetbyDates<-data[data$Date %in% c("1/2/2007", "2/2/2007"), ]

# Get the variables

# Get Global Active Power data
globalActivePwr<-as.numeric(subSetbyDates$Global_active_power)

# Get Global Reactive Power data
globalReactivePwr<-as.numeric(subSetbyDates$Global_reactive_power)

# Get Voltage
volt<-as.numeric(subSetbyDates$Voltage)

# Subset sub_meter data
meter1<- as.numeric(subSetbyDates$Sub_metering_1)
meter2<- as.numeric(subSetbyDates$Sub_metering_2)
meter3<- as.numeric(subSetbyDates$Sub_metering_3)

# For this chart the X-axis need to map the date using this notation %d/%m/%Y %H:%M:%S
date_ref<-strptime(paste(subSetbyDates$Date, subSetbyDates$Time, sep=" "), "%d/%m/%Y %H:%M:%S")


# Prepare output graphic device
png("plot4.png", width=480, heigh=480)

# This plot needs to present the 4 charts in the single image, let's update the graphical parameters
par(mfrow=c(2,2))

# First Plot on the set
plot(date_ref, globalActivePwr, type="l", xlab="", ylab="Global Active Power")

# 2nd plot -voltage
plot(date_ref, volt, type="l", xlab="datetime", ylab="Voltage")

# 3rd plot - sub meters

plot(date_ref, meter1, type="l", xlab="", ylab="Energy Submetering")
lines(date_ref, meter2, type="l", col="red")
lines(date_ref, meter3, type="l", col="blue")
legend("topright", c("Sub_metering_1", "Sub_metering_2", "Sub_metering_3"), lty=1, lwd=2.5, col=c("black", "red", "blue"))

# 4th plot - global Reactive power
plot(date_ref, globalReactivePwr, type="l", xlab="datetime", ylab="Global Reactive Power")

dev.off()