# Step chart of NASA GISS annual temperature anomaly (C) data
## STEP 1: SETUP
setwd('C:/R_Home/Charts & Graphs Blog/GISS_Temp_Anom/')
link =  c("GISS_Temp.txt")
# STEP 2: READ DATA
my_Data <- read.table(link,
             skip = 0, sep = "", dec=".",
             row.names = NULL, header = FALSE,
             colClasses <- rep("numeric",3),
             comment.char = "#", na.strings = c("*", "-",-99.9, -999.9),
             col.names <- c("Yr", "Ann_Anomaly", "5_Yr_Mean") )
# STEP 3: MANIPULATE DATA
  # Construct chart title - use 2 lines w/ \n
  Title <- paste("Annual Surface Air Temperature Anomaly  \n Based on Meterologic Stations (1880 - 2007)" )
## STEP 4: CREATE PLOT
   par(las = 1)       # Sets Y axis label orientation to vertical, set text font sizes
   par(cex.main=0.8); par(cex.sub=0.7); par(cex.lab = 0.8); par(cex.axis =.75)
plot(Ann_Anomaly ~ Yr, my_Data,
         ylim = c(-1,1),
         type=c("s"),
         col = "dark grey",
         xlab = "",
         asp = "full",
         ylab = expression(paste("Annual Temperature Anomaly - ",degree, "C (Baseline: 1951-1980)")),
         main = Title,
         sub = "Source: NASA - GISS @ http://data.giss.nasa.gov/gistemp/graphs/Fig.A.txt")
lines(lowess(my_Data$Ann_Anomaly ~ my_Data$Yr, f=0.15),col = "blue" )
arrows(1951,-.5, 1980, -.5, code = 3, angle = 20, col = "dark grey")
abline(h=0, col = "grey")          # o.o horizontal line
text(1965, -.495, "Baseline\n Period\n1951-1980", cex = 0.6, pos=3)
text(1910, -0.95, "Lowess smoother fit, f = 0.15", cex =0.65, pos = 1 )
points(c(1881,1890), c(-1,-1), col="blue",  type = "l")