# CVEN 5454 - Lecture 2, 01/16/2020
# Part II
#
# Next we'll go over a more complicated example of using boxplot and 
# histogram functions


################################################################################
# First we will download the data from the CVEN 5454 website:
rain <- read.table("http://civil.colorado.edu/~balajir/r-session-files/aismr.txt")
names(rain) <- c('Year', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug',
                 'Sep', 'Oct', 'Nov', 'Dec') # name the columns

# we just want the rainfall data not the year column
rain_months <- rain
rain_months$Year = NULL # delete the year column

# use the boxplot function to plot many boxplots on 1 graph!
boxplot(x = rain_months, xlab="Months", ylab="Monthly rainfall in India (mm)")

# let's add the mean values for every month

# find the means of each month
# (the apply function lets you apply a statistic to each column or row of a 
# dataframe)
month_means <- apply(X=rain_months, MARGIN=2, FUN=mean) #MARGIN is the dimension

# add points to our existing boxplot
points(month_means, col='blue', pch=16)

# add lines to connect if we feel like it
lines(month_means,col='blue',lwd=4)

################################################################################
# Now let's do a more complex histogram example
# Plot histogram of each month and comment on the features..

# command for pre-allocating your graphing spaces
par(mfrow=c(3,4)) # 3,4 means we want 3 rows by 4 columns of histograms (12 months)

# define month names for titling
months <- c("Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec")

# plot 12 histograms (1 for each month) in a for loop
for(i in 1:12){
  hist(rain_months[,i], xlab="Monthly rainfall", ylab="", freq=FALSE, main="")
  title(main=c(months[i],' rainfall'))
  box() # adds a nice box
}