The project is organized in 3 folders:

• scripts: contain the various R scripts
  • get_data.R: download the source data, unzip and prepare the data frame:
    • Function name: get_data()
    • Returns a data frame with the following columns:
      • DateTime: combination of original Date and Time factors converted to POSIXlt data type
      • Global_active_power
      • Global_reactive_power
      • Voltage
      • Global_intensity
      • Sub_metering_1
      • Sub_metering_2
      • Sub_metering_3
    • Filter the source data and keeps only records for 01-02-2007 and 02-02-2007
    • If the source files were already in the folder, they're removed first
  • plot1.R: draw plot1
    • Function name: draw_plot1()
    • if TRUE is passed as parameter, generate plot1.png in plots folder
  • draw_plot2: draw plot2
    • Function name: draw_plot2()
    • if TRUE is passed as parameter, generate plot2.png in plots folder
  • draw_plot3: draw plot3
    • Function name: draw_plot3()
    • if TRUE is passed as parameter, generate plot3.png in plots folder
  • draw_plot4: draw plot4
    • Function name: draw_plot4()
    • if TRUE is passed as parameter, generate plot4.png in plots folder
  • main: executes all above functions to get the data and draw all plots into 4 png files in plots folder
• data: the get_data() function will download the source file, unzip in this folder
• plots: contains the four plots requested in the work assignment_

1. Set the working directory to the scripts folder
2. Call main() to pull the data from the source URL, read it into a data frame, then draw all four plots into individual png files within plots sub-directory: plot1.png, plot2.png, plot3.png and plot4.png