r - r : duplicate faceted geom_density and geom_density_ridges results 中的 ggplot

Question

带有小平面的 ggplot2::geom_density() 和 ggridges::geom_density_ridges() 的默认设置产生略有不同的曲线。如何修改其中一种或另一种的平滑技术以产生相同的结果？

library(tidyverse)
library(ggridges)

# standard density with facet by cyl ----
mtcars %>%
  ggplot(aes(x = mpg)) +
  geom_density(fill = "gray") +
  facet_wrap(. ~ factor(cyl, levels = c(8, 6, 4)), ncol = 1) +
  theme_minimal()

# density ridge with y = cyl ----
mtcars %>%
  ggplot(aes(x = mpg, y = factor(cyl))) +
  geom_density_ridges() +
  theme_minimal()
#> Picking joint bandwidth of 1.38

^{由 reprex package 创建于 2019-04-04 (v0.2.1)}

Answer 1

您可以使用 geom_density() 使用的相同统计数据。

library(tidyverse)
library(ggridges)

# standard density with facet by cyl ----
mtcars %>%
  ggplot(aes(x = mpg)) +
  geom_density(fill = "gray") +
  facet_wrap(. ~ factor(cyl, levels = c(8, 6, 4)), ncol = 1) +
  theme_minimal()

# density ridge with y = cyl ----
mtcars %>%
  ggplot(aes(x = mpg, y = factor(cyl))) +
  geom_density_ridges(stat = "density", aes(height = stat(density))) +
  theme_minimal()

^{由 reprex package 创建于 2019-04-04 (v0.2.1)}

或者，您可以获取 geom_density_ridges() 报告的带宽并在 geom_density() 中使用它(此处，bw = 1.38) .

library(tidyverse)
library(ggridges)

# density ridge with y = cyl ----
mtcars %>%
  ggplot(aes(x = mpg, y = factor(cyl))) +
  geom_density_ridges() +
  theme_minimal()
#> Picking joint bandwidth of 1.38

# standard density with facet by cyl ----
mtcars %>%
  ggplot(aes(x = mpg)) +
  geom_density(fill = "gray", bw = 1.38) +
  facet_wrap(. ~ factor(cyl, levels = c(8, 6, 4)), ncol = 1) +
  theme_minimal()

^{由 reprex package 创建于 2019-04-04 (v0.2.1)}

最后两个图看起来略有不同，因为它们具有不同的 x 轴限制。