R语言 | 2d概率密度分布图

1个变量的分布可以用hist，两个变量呢？可以用等高线图、登高颜色图。

1. 效果图

2. 源代码

# 2d概率密度图
library(ggplot2)
p1=ggplot(faithful, aes(eruptions, waiting) )

plots=list()

#1. 散点图
plots[[1]]=p1 + 
  geom_point(colour = "black") + 
  theme_bw()+ggtitle("1")

# 等高线图
plots[[2]]=p1 + 
  stat_density2d(color = "black", size = 1) + 
  theme_bw()+ggtitle("2")

# 散点图+等高线
plots[[3]]=p1 +
  stat_density2d(color = "black", size = 1) + 
  geom_point(colour = "black") + 
  theme_bw()+ggtitle("3")


# 将密度映射到等高线
plots[[4]]=p1 +
  #stat_density2d(aes(color = ..level..), size = 1.5) + 
  stat_density2d(aes(color = after_stat(level) ), linewidth = 1.5) + 
  geom_point(colour = "black") + 
  scale_color_distiller(palette = "RdYlGn") + 
  theme_bw()+ggtitle("4")


#2. geom = "tile" 绘制颜色表示的密度图
plots[[5]]=p1 +
  stat_density2d(geom = "tile", aes(fill = ..density..), contour = FALSE) + 
  scale_fill_distiller(palette = "RdYlGn") + 
  theme_classic()+ggtitle("5")

# geom = "raster" 同上，栅格化
plots[[6]]=p1 +
  stat_density2d(geom = "raster", aes(fill = ..density..), contour = FALSE) + 
  scale_fill_distiller(palette = "RdYlGn")  + 
  theme_bw()+ggtitle("6")

# 对带宽进行调整
plots[[7]]=p1 +
  stat_density2d(geom = "raster", aes(fill = ..density..), 
                 contour = FALSE, 
                 h = c(1, 5)) +  # 修改带宽,h参数传参给 kde2d()产生密度估计 >?kde2d
  scale_fill_distiller(palette = "RdYlGn")  + 
  theme_bw()+ggtitle("7")
#h	 Bandwidth (vector of length two). If NULL, estimated using MASS::bandwidth.nrd().

# 3. 综合
plots[[8]]=p1 +
  stat_density2d(geom = "raster", aes(fill = ..density..), contour = FALSE) + 
  stat_density2d(color = "black", size = 0.7) + 
  geom_point(colour = "black", size=1) + 
  scale_fill_distiller(palette = "RdYlGn")  + 
  theme_classic()+ggtitle("8")

# 细节调整
plots[[9]]=p1 +
  stat_density2d(geom = "raster", aes(fill = ..density..), contour = F) + 
  #stat_density2d(color = "black", size = 0.6, bins=8) + 
  stat_density2d(color = "black", size = 0.6, binwidth=0.0035) + 
  geom_point(colour = "black", size=0.8) + 
  scale_fill_gradient2(low = "navy", 
                      mid = "#FFF200", midpoint = 0.012,
                      high="#ED1C24")  +
  theme_classic()+ggtitle("9")

# 拼接图
patchwork::wrap_plots(plots, ncol = 3)

Ref

• https://r-graphics.org/RECIPE-DISTRIBUTION-DENSITY2D.html
• https://r-graphics.org/RECIPE-DISTRIBUTION-BASIC-DENSITY.html