# R-code for multidimensional scaling

# The data set eurodist contains the road distances (in km) between 
# 21 cities in Europe. Based on these data, we can construct a map 
# of the location of the cities. Since the road distances do not correspond
# exactly to geographical distances, the map is only approximately correct

loc <- cmdscale(eurodist)
x <- loc[,1]
y <- -loc[,2]
plot(x, y, type="n", xlab="", ylab="", main="cmdscale(eurodist)")
text(x, y, rownames(loc), cex=0.8)

# iris data

loc <- cmdscale(dist(iris[,1:4]))
x <- loc[,1]
y <- loc[,2]
plot(x, y, type="n", xlab="", ylab="", main="cmdscale(dist(iris))")
text(x, y, c(1:150), col=c(rep("red",50), rep("blue",50), rep("orange",50)))