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ggplot中多个填充的传说

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我是 ggplot2 的初学者 . 所以，如果这个问题听起来太基本，我道歉 . 我已经花了4个小时在这上面看了这个SO线程R: Custom Legend for Multiple Layer ggplot作为指导，但结果无处可去 .

Objective: 我希望能够将图例应用于用于不同图层的不同填充颜色 . 我正在做这个例子只是为了测试我对应用概念 ggplot2 概念的理解 .

另外，我想 NOT 想要改变形状类型;改变填充颜色很好 - 通过"fill"我不是说我们可以改变"color" . 所以，如果你能纠正我工作中的错误，我将不胜感激 .

Try 1: 这是没有手动设置任何颜色的裸骨代码 .

ggplot(mtcars, aes(disp,mpg)) +
geom_point(aes(fill = factor(vs)),shape = 23, size = 8, alpha = 0.4) +
geom_point (aes(fill = factor(cyl)),shape = 21, size = 2) +
geom_rect(aes(xmin = min(disp)-5, ymax = max(mpg) + 2,fill = "cyan"), 
xmax = mean(range(mtcars$disp)),ymin = 25, alpha = 0.02) ##region for high mpg

输出如下所示：
enter image description here

现在，此图像存在一些问题：

Issue 1) 显示"high mpg areas"的青色矩形已失去其传奇 .

Issue 2) ggplot尝试组合两个 geom_point() 图层的图例，因此两个 geom_point() 的图例也是混合的 .

Issue 3) ggplot2 使用的默认颜色paleltte使我的眼睛无法区分颜色 .

所以，我采取了手动设置颜色的方法，即上面固定＃3 .

ggplot(mtcars, aes(disp,mpg)) + 
       geom_point(aes(fill = factor(vs)),shape = 23, size = 8, alpha = 0.4)+
       geom_point(aes(fill = factor(cyl)),shape = 21, size = 2) +
       geom_rect(aes(xmin = min(disp)-5, ymax = max(mpg) + 2,fill = "cyan"),
                 xmax = mean(range(mtcars$disp)),ymin = 25, alpha = 0.02) + 
     scale_fill_manual(values = c("green","blue", "black", "cyan", "red", "orange"), 
labels=c("4 gears","6 gears","8 gears","High mpg","0","1"))

这是输出：
enter image description here
不幸的是，上面强调的一些问题仍然存在 . 有关订购的新问题 .

Issue#4: 在我看来， ggplot2 希望我按照图层设置的顺序提供颜色 . 即首先设置 mtcars$vs 填充的颜色，然后设置 mtcars$cyl 填充，最后设置青色矩形 . 我能够通过修改代码来修复它：

ggplot(mtcars, aes(disp,mpg)) + 
       geom_point(aes(fill = factor(vs)),shape = 23, size = 8, alpha = 0.4) +
       geom_point(aes(fill = factor(cyl)),shape = 21, size = 2) +
       geom_rect(aes(xmin = min(disp)-5, ymax = max(mpg) + 2,fill = "cyan"),
                 xmax = mean(range(mtcars$disp)),ymin = 25, alpha = 0.02) + 
     scale_fill_manual(values = c("red", "orange", "green", "blue", "black", "cyan"), 
labels=c("0","1","4 gears","6 gears","8 gears","High mpg")) #changed the order

所以，我有两个问题：

Question 1: 如何修复图例 - 我想要三个不同的图例 - 一个用于矩形填充（我称之为高mpg矩形），另一个用于填充 geom_point() 由 mtcars$vs 表示，最后一个用于填充 geom_point() 由 mtcars$cyl 表示

Question2: 我的假设是按照正确的层次排序颜色（即上面讨论的问题＃4）？我很怀疑，因为如果有很多因素，我们需要记住它们，然后按照绘制的图层对它们进行排序，最后记得按照每个 geom_*() 图层的顺序手动应用调色板吗？

作为一个初学者，我花了很多时间在这上面，谷歌搜索到处都是 . 所以，我很感激你的善意指导 .

r ggplot2

2 回答

  • 7

    （注意，我编辑了这个以便在几次来回之后进行清理 - 请参阅修订历史以了解更多我尝试过的内容 . ）

    标度实际上是为了显示一种类型的数据 . 一种方法是同时使用 col 和 fill ，这可以让你获得至少2个传说 . 然后你可以使用 override.aes 添加 linetype 并稍微破解它 . 值得注意的是，我认为这可能（通常）会引发更多问题，而不是解决问题 . 如果你迫切需要这样做，你可以（例如下面的例子） . 但是，如果我能说服你：我恳请你尽可能不使用这种方法 . 映射到不同的东西（例如 shape 和 linetype ）可能会减少混淆 . 我举一个下面的例子 .

    此外，在手动设置颜色或填充时，使用 palette 的命名向量始终是一个好主意，以确保颜色与您想要的颜色匹配 . 如果不是，则匹配按因子级别的顺序发生 .

    ggplot(mtcars, aes(x = disp
                   , y = mpg)) +
  ##region for high mpg 
  geom_rect(aes(linetype = "High MPG")
            , xmin = min(mtcars$disp)-5
            , ymax = max(mtcars$mpg) + 2
            , fill = "cyan"
            , xmax = mean(range(mtcars$disp))
            , ymin = 25
            , alpha = 0.02
            , col = "black") + 
  ## test diff region
  geom_rect(aes(linetype = "Other Region")
            , xmin = 300
            , xmax = 400
            , ymax = 30
            , ymin = 25
            , fill = "yellow"
            , alpha = 0.02
            , col = "black") + 
  geom_point(aes(fill = factor(vs)),shape = 23, size = 8, alpha = 0.4) +
  geom_point (aes(col = factor(cyl)),shape = 19, size = 2) +
  scale_color_manual(values = c("4" = "red"
                                , "6" = "orange"
                                , "8" = "green")
                     , name = "Cylinders") +
  scale_fill_manual(values = c("0" = "blue"
                               , "1" = "black"
                               , "cyan" = "cyan")
                    , name = "V/S"
                    , labels = c("0?", "1?", "High MPG")) +
  scale_linetype_manual(values = c("High MPG" = 0
                                   , "Other Region" = 0)
                        , name = "Region"
                        , guide = guide_legend(override.aes = list(fill = c("cyan", "yellow")
                                                                       , alpha = .4)))

    enter image description here

    Here is the plot I think will work better for nearly all use cases:

    ggplot(mtcars, aes(x = disp
                   , y = mpg)) +
  ##region for high mpg 
  geom_rect(aes(linetype = "High MPG")
            , xmin = min(mtcars$disp)-5
            , ymax = max(mtcars$mpg) + 2
            , fill = NA
            , xmax = mean(range(mtcars$disp))
            , ymin = 25
            , col = "black") + 
  ## test diff region
  geom_rect(aes(linetype = "Other Region")
            , xmin = 300
            , xmax = 400
            , ymax = 30
            , ymin = 25
            , fill = NA
            , col = "black") +
  geom_point(aes(col = factor(cyl)
                 , shape = factor(vs))
             , size = 3) +
  scale_color_brewer(name = "Cylinders"
                     , palette = "Set1") +
  scale_shape(name = "V/S") +
  scale_linetype_manual(values = c("High MPG" = "dotted"
                                   , "Other Region" = "dashed")
                        , name = "Region")

    enter image description here

    出于某种原因，你坚持使用 fill . 这是一种方法，与本答案中的第一个完全相同，但使用 fill 作为每个层的美学 . 如果这不是你坚持的，那么我仍然不知道你在寻找什么 .

    ggplot(mtcars, aes(x = disp
                   , y = mpg)) +
  ##region for high mpg 
  geom_rect(aes(linetype = "High MPG")
            , xmin = min(mtcars$disp)-5
            , ymax = max(mtcars$mpg) + 2
            , fill = "cyan"
            , xmax = mean(range(mtcars$disp))
            , ymin = 25
            , alpha = 0.02
            , col = "black") + 
  ## test diff region
  geom_rect(aes(linetype = "Other Region")
            , xmin = 300
            , xmax = 400
            , ymax = 30
            , ymin = 25
            , fill = "yellow"
            , alpha = 0.02
            , col = "black") + 
  geom_point(aes(fill = factor(vs)),shape = 23, size = 8, alpha = 0.4) +
  geom_point (aes(col = "4")
              , data = mtcars[mtcars$cyl == 4, ]
              , shape = 21
              , size = 2
              , fill = "red") +
  geom_point (aes(col = "6")
              , data = mtcars[mtcars$cyl == 6, ]
              , shape = 21
              , size = 2
              , fill = "orange") +
  geom_point (aes(col = "8")
              , data = mtcars[mtcars$cyl == 8, ]
              , shape = 21
              , size = 2
              , fill = "green") +
  scale_color_manual(values = c("4" = NA
                                , "6" = NA
                                , "8" = NA)
                     , name = "Cylinders"
                     , guide = guide_legend(override.aes = list(fill = c("red","orange","green")))) +
  scale_fill_manual(values = c("0" = "blue"
                               , "1" = "black"
                               , "cyan" = "cyan")
                    , name = "V/S"
                    , labels = c("0?", "1?", "High MPG")) +
  scale_linetype_manual(values = c("High MPG" = 0
                                   , "Other Region" = 0)
                        , name = "Region"
                        , guide = guide_legend(override.aes = list(fill = c("cyan", "yellow")
                                                                   , alpha = .4)))

    因为我显然不能单独留下这一点 - 这是另一种方法，只使用填充美学，然后为单个图层制作单独的图例并使用 cowplot 松散地将它们拼接在一起tutorial .

    library(cowplot)
library(dplyr)

theme_set(theme_minimal())

allScales <-
  c("4" = "red"
    , "6" = "orange"
    , "8" = "green"
    , "0" = "blue"
    , "1" = "black"
    , "High MPG" = "cyan"
    , "Other Region" = "yellow")

mainPlot <-
  ggplot(mtcars, aes(x = disp
                     , y = mpg)) +
  ##region for high mpg 
  geom_rect(aes(fill = "High MPG")
            , xmin = min(mtcars$disp)-5
            , ymax = max(mtcars$mpg) + 2
            , xmax = mean(range(mtcars$disp))
            , ymin = 25
            , alpha = 0.02) + 
  ## test diff region
  geom_rect(aes(fill = "Other Region")
            , xmin = 300
            , xmax = 400
            , ymax = 30
            , ymin = 25
            , alpha = 0.02) + 
  geom_point(aes(fill = factor(vs)),shape = 23, size = 8, alpha = 0.4) +
  geom_point (aes(fill = factor(cyl)),shape = 21, size = 2) +
  scale_fill_manual(values = allScales)

vsLeg <-
  (ggplot(mtcars, aes(x = disp
                      , y = mpg)) +
     geom_point(aes(fill = factor(vs)),shape = 23, size = 8, alpha = 0.4) +
     scale_fill_manual(values = allScales
                       , name = "VS")
  ) %>%
  ggplotGrob %>%
  {.$grobs[[which(sapply(.$grobs, function(x) {x$name}) == "guide-box")]]}



cylLeg <-
  (ggplot(mtcars, aes(x = disp
                      , y = mpg)) +
     geom_point (aes(fill = factor(cyl)),shape = 21, size = 2) +
     scale_fill_manual(values = allScales
                       , name = "Cylinders")
  ) %>%
  ggplotGrob %>%
  {.$grobs[[which(sapply(.$grobs, function(x) {x$name}) == "guide-box")]]}


regionLeg <-
  (ggplot(mtcars, aes(x = disp
                      , y = mpg)) +
     geom_rect(aes(fill = "High MPG")
               , xmin = min(mtcars$disp)-5
               , ymax = max(mtcars$mpg) + 2
               , xmax = mean(range(mtcars$disp))
               , ymin = 25
               , alpha = 0.02) + 
     ## test diff region
     geom_rect(aes(fill = "Other Region")
               , xmin = 300
               , xmax = 400
               , ymax = 30
               , ymin = 25
               , alpha = 0.02) + 
     scale_fill_manual(values = allScales
                       , name = "Region"
                       , guide = guide_legend(override.aes = list(alpha = 0.4)))
  ) %>%
  ggplotGrob %>%
  {.$grobs[[which(sapply(.$grobs, function(x) {x$name}) == "guide-box")]]}


legendColumn <-
  plot_grid(
    # To make space at the top
    vsLeg + theme(legend.position = "none")
    # Plot the legends
    , vsLeg, regionLeg, cylLeg
    # To make space at the bottom
    , vsLeg + theme(legend.position = "none")
    , ncol = 1
    , align = "v")

plot_grid(mainPlot +
            theme(legend.position = "none")
          , legendColumn
          , rel_widths = c(1,.25))

    enter image description here

    正如您所看到的，结果几乎与我演示如何执行此操作的第一种方式相同，但现在不使用任何其他美学 . 我仍然不明白为什么你认为这种区别是重要的，但至少现在有另一种方法可以给猫皮肤 . 我可以使用这种方法的一般性（例如，当多个绘图共享颜色/符号/线型美学混合并且您想要使用单个图例时）但我认为在此处使用它没有任何 Value .

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  • 0

    你也可以实现这是通过使用 cowplot 中的 align_plots 和 ggdraw 函数分层多个图 . 这是我用于将散射（离散色标）放到光栅上的解决方案（连续色标） . 请参阅以下链接中的插图 .

    https://www.rdocumentation.org/packages/cowplot/versions/0.9.2/topics/align_plots

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