r - 从两个数据框构建绘图时的两个图例

Question

我有两个这样的数据框:

library(ggplot2)

set.seed(1)
x1 = rnorm(100)
y1 = rnorm(100)

x2 = rnorm(100)
y2 = rnorm(100)

df1  = data.frame(x=x1, y=y1, col1 = rep(1:4, each = 25))
df2 = data.frame(x=x2, y=y2, col2 = rep(5:8, each = 25))

我绘制了这个数据:

ggplot() +
  geom_point(aes(x = x1, y = y1,  colour = as.factor(col1)), data = df1, size = 1, shape = 19) +
  geom_point(aes(x = x2, y = y2,  colour = as.factor(col2)), data = df2, size = 2, shape = "\u2605")

结果是这样的:

如何为每个数据框获得两个单独的图例？
图例还应正确反射(reflect)所使用的形状，并让我为每个图例指定图例标题。
我知道 this solution存在但它很旧并且需要可以填充的符号，我想使用自定义的unicode符号。

Answer 1

这可以通过 ggnewscale 实现允许具有相同美学的额外比例和图例的包。尝试这个:

library(ggplot2)

set.seed(1)
x1 = rnorm(100)
y1 = rnorm(100)

x2 = rnorm(100)
y2 = rnorm(100)

df1  = data.frame(x=x1, y=y1, col1 = rep(1:4, each = 25))
df2 = data.frame(x=x2, y=y2, col2 = rep(5:8, each = 25))

ggplot() +
  geom_point(aes(x = x1, y = y1,  colour = as.factor(col1)), data = df1, size = 1, shape = 19) +
  ggnewscale::new_scale_color() +
  geom_point(aes(x = x2, y = y2,  colour = as.factor(col2)), data = df2, size = 2, shape = "\u2605")