これはおそらくこれを行うための最もエレガントな方法ではありませんが、機能します(最初から使用せternaryplot
ずに:それを行う方法を理解できませんでした)。
a<- c (0.1, 0.5, 0.5, 0.6, 0.2, 0, 0, 0.004166667, 0.45)
b<- c (0.75,0.5,0,0.1,0.2,0.951612903,0.918103448,0.7875,0.45)
c<- c (0.15,0,0.5,0.3,0.6,0.048387097,0.081896552,0.208333333,0.1)
d<- c (500,2324.90,2551.44,1244.50, 551.22,-644.20,-377.17,-100, 2493.04)
df<- data.frame (a, b, c)
# First create the limit of the ternary plot:
plot(NA,NA,xlim=c(0,1),ylim=c(0,sqrt(3)/2),asp=1,bty="n",axes=F,xlab="",ylab="")
segments(0,0,0.5,sqrt(3)/2)
segments(0.5,sqrt(3)/2,1,0)
segments(1,0,0,0)
text(0.5,(sqrt(3)/2),"c", pos=3)
text(0,0,"a", pos=1)
text(1,0,"b", pos=1)
# The biggest difficulty in the making of a ternary plot is to transform triangular coordinates into cartesian coordinates, here is a small function to do so:
tern2cart <- function(coord){
coord[1]->x
coord[2]->y
coord[3]->z
x+y+z -> tot
x/tot -> x # First normalize the values of x, y and z
y/tot -> y
z/tot -> z
(2*y + z)/(2*(x+y+z)) -> x1 # Then transform into cartesian coordinates
sqrt(3)*z/(2*(x+y+z)) -> y1
return(c(x1,y1))
}
# Apply this equation to each set of coordinates
t(apply(df,1,tern2cart)) -> tern
# Intrapolate the value to create the contour plot
resolution <- 0.001
require(akima)
interp(tern[,1],tern[,2],z=d, xo=seq(0,1,by=resolution), yo=seq(0,1,by=resolution)) -> tern.grid
# And then plot:
image(tern.grid,breaks=c(-1000,0,500,1000,1500,2000,3000),col=rev(heat.colors(6)),add=T)
contour(tern.grid,levels=c(-1000,0,500,1000,1500,2000,3000),add=T)
points(tern,pch=19)