覆蓋密度

Question

我有一些數據：

dat <- data.frame(x=rnorm(100,100,100),y=rnorm(100,100,100)) 

我可以與當地的趨勢線繪製它：

ggplot(dat, aes(x,y)) + stat_smooth() 

但我想覆蓋的密度曲線，上同樣的情節，顯示x的分佈。因此，只要之前的圖形添加到此一（y軸是不同的，但我只關心在密度曲線的相對差異反正）：

ggplot(dat, aes(x)) + geom_density() 

我知道有stat_binhex()和stat_sum()等表示將數據瀑布。只有幾個y值，所以被stat_binhex()等等繪製出來的東西很難看清楚。

Answer 1

您可以在散點圖的兩側繪製直方圖和密度曲線的組合。在下面的例子中我還包括一個置信橢圓：

require(ggplot2) 
require(gridExtra) 
require(devtools) 
source_url("https://raw.github.com/low-decarie/FAAV/master/r/stat-ellipse.R") # in order to create a 95% confidence ellipse 

htop <- ggplot(data=dat, aes(x=x)) + 
    geom_histogram(aes(y=..density..), fill = "white", color = "black", binwidth = 2) + 
    stat_density(colour = "blue", geom="line", size = 1.5, position="identity", show_guide=FALSE) + 
    scale_x_continuous("x-var", limits = c(-200,400), breaks = c(-200,0,200,400)) + 
    scale_y_continuous("Density", breaks=c(0.0,0.01,0.02), labels=c(0.0,0.01,0.02)) + 
    theme_bw() + theme(axis.title.x = element_blank()) 

blank <- ggplot() + geom_point(aes(1,1), colour="white") + 
    theme(axis.ticks=element_blank(), panel.background=element_blank(), panel.grid=element_blank(), 
     axis.text.x=element_blank(), axis.text.y=element_blank(), axis.title.x=element_blank(), axis.title.y=element_blank()) 

scatter <- ggplot(data=dat, aes(x=x, y=y)) + 
    geom_point(size = 0.6) + stat_ellipse(level = 0.95, size = 1, color="green") + 
    scale_x_continuous("x-var", limits = c(-200,400), breaks = c(-200,0,200,400)) + 
    scale_y_continuous("y-var", limits = c(-200,400), breaks = c(-200,0,200,400)) + 
    theme_bw() 

hright <- ggplot(data=dat, aes(x=y)) + 
    geom_histogram(aes(y=..density..), fill = "white", color = "black", binwidth = 1) + 
    stat_density(colour = "red", geom="line", size = 1, position="identity", show_guide=FALSE) + 
    scale_x_continuous("y-var", limits = c(-200,400), breaks = c(-200,0,200,400)) + 
    scale_y_continuous("Density", breaks=c(0.0,0.01,0.02), labels=c(0.0,0.01,0.02)) + 
    coord_flip() + theme_bw() + theme(axis.title.y = element_blank()) 

grid.arrange(htop, blank, scatter, hright, ncol=2, nrow=2, widths=c(4, 1), heights=c(1, 4)) 

結果：