plot3.R

#Reference UDFs
source("./udf.R")

#Define function for building the plot png file
plot3 <- function(dframes=NULL){
	packages <- c("dplyr","ggplot2")
	packagechecks <- checkPackages(packages)

	if(is.null(dframes)){
		dframes <- loaddata()
	}

	pmdf <- data.frame(dframes[1])
	summary <- data.frame(dframes[2])

#Begin Analysis
	summary.baltimore <- transform(subset(summary, summary$fips == "24510"), type = factor(type))

	# Set bg color transparent
	par(bg = "transparent")

	# Start device
	png(file = "plot3.png", width=1200, height=800)

	# Draw plot 3
	print({
		g <- qplot(year, Emissions, 
			data = summary.baltimore, 
			geom = c("point","smooth"), 
			method = "lm", 
			facets = .~type)

		g + geom_point() + coord_cartesian(ylim = (c(0,100)))
	}
	)
	# Close the device
	dev.off()

	#Answer, They all have but nonpoint and point have shown the greatest decreases according to this graph. 
}
#Call the Function
plot3()