如何将两个不同比例的颜色渐变与ggplot合并 [英] How merge two different scale color gradient with ggplot

问题描述

通过使用R，是否可以将2个ggplot放在一起(即，在同一图上)，但是具有不同的颜色渐变条形?我的代码，例如

By using R, is it possible to place 2 ggplot together (i.e., on the same plot) but with different bar of color gradient? My code, e.g.,

library(ggplot2)
ggplot(df1, aes(duration, slopes, col = color)) +
 geom_point(size = 3) +
 scale_color_gradient(low = "black", high = "red")
ggplot(df2, aes(duration, slopes, col = color)) +
 geom_point(size = 3) +
 scale_color_gradient(low = "blue", high = "green")

产生以下两张图片

我希望能够将它们整合在一起，在一个图中用红色和黑色的条形图和蓝色和绿色的另一条形图.

I wish instead to be able to integrate them together in one plot with a bar for red and black and another bar for blue and green.

推荐答案

是的，如果您使用 ggnewscale 包，则可以:

Yes you could if you use the ggnewscale package:

a <- sample(nrow(iris), 75)

df1 <- iris[a,]
df2 <- iris[-a,]

library(ggnewscale)

ggplot(mapping = aes(Sepal.Width, Sepal.Length)) +
  geom_point(data = df1, aes(colour = Petal.Length)) +
  scale_colour_gradientn(colours = c("red", "black")) +
  # Important: define a colour/fill scale before calling a new_scale_* function
  new_scale_colour() +
  geom_point(data = df2, aes(colour = Petal.Width)) +
  scale_colour_gradientn(colours = c("blue", "white"))

替代方法是 relayer 包，或者是 scale_colour_multi / scale_listed 来自 ggh4x (完整免责声明:我写了ggh4x).

Alternatives are the relayer package, or the scale_colour_multi/scale_listed from ggh4x (full disclaimer: I wrote ggh4x).

以下是替代方法:

library(ggh4x)

# ggh4x scale_colour_multi (for gradientn-like scales)
ggplot(mapping = aes(Sepal.Width, Sepal.Length)) +
  geom_point(data = df1, aes(length = Petal.Length)) +
  geom_point(data = df2, aes(width = Petal.Width)) +
  scale_colour_multi(colours = list(c("red", "black"), c("blue", "white")),
                     aesthetics = c("length", "width"))

# ggh4x scale_listed (for any non-position scale (in theory))
ggplot(mapping = aes(Sepal.Width, Sepal.Length)) +
  geom_point(data = df1, aes(length = Petal.Length)) +
  geom_point(data = df2, aes(width = Petal.Width)) +
  scale_listed(list(
    scale_colour_gradientn(colours = c("red", "black"), aesthetics = "length"),
    scale_colour_gradientn(colours = c("blue", "white"), aesthetics = "width")
  ), replaces = c("colour", "colour"))


library(relayer)

# relayer
ggplot(mapping = aes(Sepal.Width, Sepal.Length)) +
  rename_geom_aes(geom_point(data = df1, aes(length = Petal.Length)), 
                  new_aes = c("colour" = "length")) +
  rename_geom_aes(geom_point(data = df2, aes(width = Petal.Width)),
                  new_aes = c("colour" = "width")) +
  scale_colour_gradientn(colours = c("red", "black"), aesthetics = "length", 
                         guide = guide_colourbar(available_aes = "length")) +
  scale_colour_gradientn(colours = c("blue", "white"), aesthetics = "width", 
                         guide = guide_colourbar(available_aes = "width"))

所有其他选择都会发出有关未知美学的警告，但这与生成的图无关紧要.这只是ggplot的 layer()函数中的一行代码，会产生此警告，如果不重新编码每个 geom 包装器或ggnewscale确实做到了，重命名了旧的美学而不是提供了新的美学.这些图看起来都差不多，因此我认为不必再次发布它们.

All the alternatives give warnings about unknown aesthetics, but this doesn't matter for the resulting plots. It is just a line of code in ggplot's layer() function that produces this warning and you can't go around this without either re-coding every geom wrapper or, as ggnewscale does, renaming the old aesthetic instead of providing a new aesthetic. The plots all look near-identical, so I figured I wouldn't have to post them again.

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