在ggplot中添加多个图例

Question

在ggplot中添加多个图例

3

我有一个多层次的图表：

df <- data.frame(number = 1:10, 
                 values = rnorm(10), 
                 decision = factor(rbinom(10,1,.5), levels = c(0,1),
                                   labels=c("No","Yes")),
                 expValues = rnorm(10),
                 bandwidth = runif(10, 0,1))

ggplot(df,aes(x = number, y = values, color=decision)) + aes(group=NA) +
  geom_line(size = 1) + 
  geom_point(size = 3,shape = 16) + 
  geom_smooth(data = df, aes(ymin = values-bandwidth , ymax = values+bandwidth), 
              stat = "identity") +
  geom_point(data=df,
             aes(x=number,y=expValues),shape = "x", size = 5, color = "blue") +
  geom_text(data = data.frame(x = Inf, y = max(df$values), label = "Mean  = 12"), 
            aes(label=label, x =  x, y = y) ,
            hjust = 1, vjust = -0.1, color = "brown", size = 10) +
  geom_hline(yintercept=mean(df$values) ,color="blue", linetype = "dashed") +
  theme(text=element_text(size=20))

输入图像描述

我想为geom_hline和geom_point添加图例，形状为"x"，分别表示第一个图例为"切割值"，第二个图例为"期望值"。

我该如何做呢？

注意：我查看了此帖子和此帖子以获取可能的解决方案，但无法弄清楚如何特别针对geom_hline进行操作。

- HBat

http://docs.ggplot2.org/current/guides.html - N8TRO

@N8TRO，我从页面上了解到，在ggplot()中使用的主要data.frame中，可以为不同的比例尺添加图例。但是从你提供的链接页面上并不明显如何为例如geom_hline()添加图例。您能否详细分享一下您的见解？ - HBat

1个回答

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- aosmith · Accepted Answer

要添加图例，首先需要将某些内容映射到所需的美学功能。例如，您现在将点形状设置为“x”，但未在“aes”中进行映射，因此不会得到图例。您可以将其映射到常量以及变量以强制生成图例。

对于您的“geom_point”层，只需将“shape”移动到“aes”内部，并映射到任何常量即可。使用指示其含义的某个值将使图例编辑更加容易。

geom_point(data=df, aes(x=number, y=expValues, shape = "Expected value"), size = 5, color = "blue")

对于geom_hline，您需要一个特定于该层的数据集进行映射。根据您选择的路径，您可能还需要在此图层中将show_guide设置为TRUE。

geom_hline(data = data.frame(yint = mean(df$values)), aes(...), show_guide = TRUE)

你可以制作两个分开的图例。你也可以将线条和形状合并成为单个图例，就像这个回答 here 中所示。这两个选项都需要在适当的scale_xxx_manual设置值，并在guide_legend中使用override.aes。

以下是创建单个新图例的方法。请注意，在geom_line之前添加geom_hline以使decision图例显示正确。

ggplot(df, aes(x = number, y = values, color=decision, group = NA)) +
    geom_hline(data = data.frame(yint = mean(df$values)),
        aes(yintercept = yint, shape = "Cut value"), 
             color="blue", linetype = 2, show_guide = TRUE) +
    geom_line(size = 1) + 
    geom_point(size = 3,shape = 16) + 
    geom_smooth(data = df, aes(ymin = values-bandwidth , ymax = values+bandwidth), 
              stat = "identity") +
    geom_point(data=df, aes(x=number, y=expValues, shape = "Expected value"), 
             size = 5, color = "blue") +
    geom_text(data = data.frame(x = Inf, y = max(df$values), label = "Mean  = 12"), 
        aes(label=label, x =  x, y = y),
        hjust = 1, vjust = -0.1, color = "brown", size = 10) +      
    theme(text=element_text(size=20)) +
    scale_shape_manual(name = "", values = c("x", "x")) +
    guides(shape = guide_legend(override.aes = list(linetype = c(2, 0), 
                                            shape = c(NA, "x"))))

编辑添加误差带区域的图例

我无法通过使用fill来添加基于误差带区域的第三个图例。虽然您可以将其作为三个单独的图例，但我认为间距不太好:

ggplot(df, aes(x = number, y = values, color=decision, group = NA)) +
    geom_hline(data = data.frame(yint = mean(df$values)),
        aes(yintercept = yint, linetype = "Cut value"), 
             color="blue", show_guide = TRUE) +
    geom_line(size = 1) + 
    geom_point(size = 3,shape = 16) + 
    geom_smooth(data = df, aes(ymin = values-bandwidth , ymax = values+bandwidth, fill = "Error band"), 
              stat = "identity") +
    geom_point(data=df, aes(x=number, y=expValues, shape = "Expected value"), 
             size = 5, color = "blue") +
    geom_text(data = data.frame(x = Inf, y = max(df$values), label = "Mean  = 12"), 
        aes(label=label, x =  x, y = y),
        hjust = 1, vjust = -0.1, color = "brown", size = 10) +  
    theme(text=element_text(size=20)) +
    scale_shape_manual(name = "", values = "x") +
    scale_linetype_manual(name = "", values = 2) +
    scale_fill_manual(name = "", values = "grey") +
    guides(shape = guide_legend(override.aes = list(linetype = 0)),
          fill = guide_legend(override.aes = list(linetype = 0)),
          color = guide_legend(override.aes = list(fill = NA)))

或者，在override.aes中进行一些工作，结合colour和size，以及linetype和shape的组合，也可以实现这一点。

ggplot(df, aes(x = number, y = values, color=decision, group = NA)) +
    geom_hline(data = data.frame(yint = mean(df$values)),
        aes(yintercept = yint, shape = "Cut value"), 
             color="blue", linetype = 2, show_guide = TRUE) +
    geom_line(size = 1) + 
    geom_point(size = 3,shape = 16) + 
    geom_smooth(data = df, aes(ymin = values-bandwidth , ymax = values+bandwidth, shape = "Error band"), 
              stat = "identity", show_guide = FALSE) +
    geom_point(data=df, aes(x=number, y=expValues, shape = "Expected value"), 
             size = 5, color = "blue") +
    geom_text(data = data.frame(x = Inf, y = max(df$values), label = "Mean  = 12"), 
        aes(label=label, x =  x, y = y),
        hjust = 1, vjust = -0.1, color = "brown", size = 10) +  
    theme(text=element_text(size=20)) +
    scale_shape_manual(name = "", values = rep("x", 3)) +
    guides(shape = guide_legend(override.aes = list(linetype = c(2, 1, 0), 
                                           size = c(.5, 10, 5),
                                           shape = c(NA, NA, "x"),
                                           colour = c("blue", "grey75", "blue"))))