#Example Four Panel Contour Plot with One Legend
#Author: Carey R McGilliard
#September 2010

#This code uses a modified version of filled.contour called filled.contour3 (created by Carey McGilliard, Ian Taylor, and Bridget Ferris)
 #to make an example figure of four contour plots sharing a legend (to the right).
 #The example demonstrates how to use various color schemes for the contour plots and legend, but the user will want to
 #pick one color scheme for all four plots such that the legend matches the plots.
 #Changing the x- and y-axis values will change the placement of text added to the figure using the text() function and adjustments will be necessary

 
#Source the following functions (change the paths as necessary)
source("http://wiki.cbr.washington.edu/qerm/images/1/16/Filled.contour3.R")
source("http://wiki.cbr.washington.edu/qerm/images/2/25/Filled.legend.R")

MakeLetter <- function(a, where="topleft", cex=2)
     legend(where, pt.cex=0, bty="n", title=a, cex=cex, legend=NA)

#------------------------------------------------------
#Generate some fake data
x = rep(c(10,11,12),length = 9)
y = rep(c(1,2,3),each = 3)
z = runif(n=9,min = 0,max = 1)


    xcoords = unique(x)
    ycoords = unique(y)
    surface.matrix = matrix(z,nrow=length(xcoords),ncol=length(ycoords),byrow=T)
#------------------------------------------------------

#plot.new() is necessary if using the modified versions of filled.contour
plot.new()

#I am organizing where the plots appear on the page using the "plt" argument in "par()"
par(new = "TRUE",plt = c(0.1,0.4,0.60,0.95),las = 1,cex.axis = 1)

#Top left plot:
filled.contour3(xcoords,ycoords,surface.matrix,color=terrain.colors,xlab = "",ylab = "",xlim = c(min(xcoords),max(xcoords)),ylim = c(min(ycoords),max(ycoords)),zlim = c(min(surface.matrix),max(surface.matrix)))
#The xpd=NA allows for writing outside the plot limits, but still using the the x and y axes to place the text
par(xpd = NA)
text(x=11,y=1.5,"x",cex = 1.5,font = 2)
MakeLetter("(a)")

#Top right plot:
par(new = "TRUE",plt = c(0.5,0.8,0.60,0.95),las = 1,cex.axis = 1)
filled.contour3(xcoords,ycoords,surface.matrix,color=heat.colors,xlab = "",ylab = "",xlim = c(min(xcoords),max(xcoords)),ylim = c(min(ycoords),max(ycoords)),zlim = c(-1,1))
#Alternatively, you could set z axis limits to depend on the min and max values in surface.matrix.
#filled.contour3(xcoords,ycoords,surface.matrix,color=heat.colors,xlab = "",ylab = "",xlim = c(min(xcoords),max(xcoords)),ylim = c(min(ycoords),max(ycoords)),zlim = c(min(surface.matrix),max(surface.matrix)))
text(x=11,y=1.5,"x",cex = 1.5,font = 2)
MakeLetter("(b)")

#Bottom left plot:
par(new = "TRUE",plt = c(0.1,0.4,0.15,0.5),las = 1,cex.axis = 1)
filled.contour3(xcoords,ycoords,surface.matrix,col=gray(seq(1,.1,length=11)), nlevels=11,xlab = "",ylab = "",xlim = c(min(xcoords),max(xcoords)),ylim = c(min(ycoords),max(ycoords)),zlim = c(-1,1))
text(x=11,y=1.5,"x",cex = 1.5,font = 2,col = "white")
MakeLetter("(c)")

#Bottom right plot:
par(new = "TRUE",plt = c(0.5,0.8,0.15,0.5),las = 1,cex.axis = 1)
filled.contour3(xcoords,ycoords,surface.matrix,color = terrain.colors,xlab = "",ylab = "",xlim = c(min(xcoords),max(xcoords)),ylim = c(min(ycoords),max(ycoords)),zlim = c(-1,1))
text(x=11,y=1.5,"hello",cex = 1.5,font = 2)
MakeLetter("(d)")

#Add a legend:
par(new = "TRUE",plt = c(0.85,0.9,0.25,0.85),las = 1,cex.axis = 1)
filled.legend(xcoords,ycoords,surface.matrix,color = terrain.colors,xlab = "",ylab = "",xlim = c(min(xintercepts),max(xintercepts)),ylim = c(min(slopes),max(slopes)),zlim = c(-1,1))

#Add some figure labels
par(xpd=NA,cex = 1.3)
text(x = -16.7,y = 0,"slope",srt = 90,cex = 1.3)
text(x = -8,y = -1.62,expression(paste(italic(x),"-intercept",sep = "")),cex = 1.3)