R中的标记似然轮廓图

Question

我有一个包含以下值的csv文件。

x,y
50.0,0.0
50.0,0.0
51.0,0.0
53.0,0.0
54.0,0.0
54.0,0.0
54.0,0.0
55.0,0.0
55.0,0.0
56.0,0.0
56.0,0.0
57.0,0.0
57.0,0.0
57.0,1.0
57.0,1.0
58.0,0.0
59.0,0.0
60.0,0.0
60.0,1.0
61.0,0.0
61.0,0.0
61.0,1.0
61.0,1.0
62.0,1.0
62.0,1.0
62.0,0.0
62.0,1.0
63.0,0.0
63.0,0.0
63.0,1.0
64.0,0.0
64.0,1.0
65.0,0.0
67.0,1.0
67.0,1.0
68.0,0.0
68.0,1.0
69.0,0.0
70.0,1.0
71.0,0.0

我可以使用contour()函数和下面的代码在R中创建一个很好的等高线图，但我想使用ggplot做同样的事情。有人可以说明如何做到这一点？我还在底部附加了一个图像，显示了当前代码的图形。 Likelihood Contour Image

#Read in the file `xy`
x<- xy$x
y<- xy$y
#Center age
x0 <- x-mean(x)
#fit glm
xglm <- glm(y~x0,family=binomial)
# 2d likelihood
b<- summary(xglm)$coef
#intercept estimate and se
b0hat<-xglm$coef[1]; se0<- b[1,2]
#slope estimate and se
b1hat<-xglm$coef[2]; se1<- b[2,2]
#Compute the log-likelihood
fun1 <- function(bo,b1){
    sum(y*(bo+b1*x0)- log(1+exp(bo+b1*x0)))
}

lik<- NULL
#get range of values within +- 3 se for intercept
bbo<- seq(b0hat-3*se0, b0hat+3*se0 ,len=20)
#get range of values within +- 3 se for slope
bb1 <- seq(b1hat-3*se1, b1hat+3*se1,len=20)
for (bo in bbo)
{
  for (b1 in bb1){
     lik <- c(lik,fun1(bo,b1))
  }
}
#get max likelihood
maxlik <- max(lik)
#get difference
lik <- lik-maxlik
#take the exponential of the likelihood
lik<- exp(lik)

contour(bbo,bb1,matrix(lik,20,byrow=T),level=seq(.1,1,by=.2),
    xlab=expression(beta[0]),
    ylab=expression(beta[1]))

Answer 1

如下所示？

library(ggplot2)
df.lik <- setNames(expand.grid(bbo, bb1), c('x', 'y')) 
vfun1 <- Vectorize(fun1, SIMPLIFY = TRUE)

df.lik$z <- vfun1(df.lik$x,df.lik$y)       
p <- ggplot(df.lik, aes(x, y, z=z)) + stat_contour(aes(colour = ..level..))
data<- ggplot_build(p)$data[[1]] 
indices <- setdiff(1:nrow(data), which(duplicated(data$level))) # distinct levels
p + 
  geom_text(aes(label=seq(0,1,by=.1), z=NULL), data=data[indices,]) +
  xlab(expression(beta[0])) +
  ylab(expression(beta[1]))