r - Geom_density_2d_filled() ggplot：（1）如何围绕所有点绘制轮廓，（2）如何改变渐变颜色？

Question

我有两个问题，我无法弄清楚我们的谷歌：

数据和ggplot：

x = rnorm(n = 500, mean = 0.5, sd = 0.3)
y = rnorm(n = 500, mean = 6, sd = 1)
data = merge(x, y, by = "row.names", all = TRUE)

data %>% ggplot(aes(x, y))+
  geom_density_2d_filled(contour_var = "ndensity", bins = 5)+
  theme_classic()

（1）如何围绕所有点绘制轮廓？目前，20% 的值与背景颜色相同。应该添加新层？

(2) 如何将背景颜色更改为白色，并将渐变颜色更改为 brewer "Blues" 调色板（所有高于 0 的值都应具有与白色背景不同的蓝色）？

标签： rggplot2

Answer 1

You'd probably want to decouple the stat from the geom, as the geom_density_2d_filled() draws polygons but also includes the outer layer as a rectangle.

Here is my suggestion:

x = rnorm(n = 500, mean = 0.5, sd = 0.3)
y = rnorm(n = 500, mean = 6, sd = 1)
data = merge(x, y, by = "row.names", all = TRUE)

data %>% ggplot(aes(x, y))+
  stat_density_2d(geom = "polygon", contour = TRUE,
                  aes(fill = after_stat(level)), colour = "black",
                  bins = 5) +
  scale_fill_distiller(palette = "Blues", direction = 1) +
  theme_classic()