rm(list=ls())  
library(MASS)   
ex11.5 <- read.table("例11-5new.txt", head=TRUE, fileEncoding="utf8")[-3,]  
dat115 <- ex11.5[, -1]  
rownames(dat115) <- ex11.5[, 1]  
head(dat115)  
x1    x2      x3      x4  
北京    10.3  12.5  2199.9 23965.7  
天津    39.7  69.3 13741.2 35033.6  
山西   113.4  37.1 17123.6 76671.8  
内蒙古 131.9  66.0 13773.8 83545.5  
辽宁   110.7 106.8   280.0 66970.0  
吉林   161.1  63.7 17415.9 52581.1  
#样本的距离矩阵  
D <- dist(dat115)  
fit115 <- MASS::isoMDS(D, k=2)  
initial  value 0.000146   
final  value 0.000146   
converged  
#fit115$points #系数  
D1 <- fit115$points[, 1]  
D2 <- fit115$points[, 2]  
#画散点图  
plot(D1, D2)  
abline(v=0, h=0, lty=2)  
text(D1, D2, labels=ex11.5[, 1]) 





