ggplot2 scale_color_identity() 如何更改图例的线型和设计？

Question

我编写了以下 ggplot。问题在于图例的设计存在缺陷：图例的元素通过虚线相互连接。如何删除？此外，海军应该是虚线，但显示为实线。有可能改变吗？这是我的代码：

plot1 <- ggplot() +
  geom_line(aes(x = datacom$Datum , y = datacom$`CDU/CSU`, colour = "black"),size=0.8) +
  geom_line(aes(x = datacom$Datum , y = datacom$SPD, colour = "red"),size=0.8) +
  geom_line(aes(x = datacom$Datum , y = datacom$GRÜNE, col = "green"),size=0.8) +
  geom_line(aes(x = datacom$Datum , y = datacom$FDP, col = "gold1"),size=0.8) +
  geom_line(aes(x = datacom$Datum , y = datacom$`Linke/PDS`, col = "darkred"),size=0.8) +
  geom_line(aes(x = datacom$Datum[154:168] , y = datacom$Piraten[154:168], col = "tan1"),size=0.8) +
  geom_line(aes(x = datacom$Datum[169:272] , y = datacom$AfD[169:272], col = "blue"),size=0.8) +
  geom_line(aes(x = datacom$Datum , y = datacom$Sonstige, col = "grey"),size=0.8) +
  geom_vline(aes(xintercept = datacom$Datum[263], color = "navy"), linetype="longdash",size = 0.5)+
  geom_vline(xintercept = datacom$Datum[215], color = "navy", size = 0.5,linetype="longdash")+
  geom_vline(xintercept = datacom$Datum[167], color = "navy", size = 0.5,linetype="longdash")+
  geom_vline(xintercept = datacom$Datum[127], color = "navy", size = 0.5,linetype="longdash")+
  geom_vline(xintercept = datacom$Datum[79], color = "navy", size = 0.5,linetype="longdash")+
  geom_vline(xintercept = datacom$Datum[44], color = "navy", size = 0.5,linetype="longdash")+
  scale_color_identity(name = NULL, labels = c(black = "CDU/CSU", red = "SPD",green="Die Grünen",gold1="FDP",darkred = "Die Linke/PDS",tan1="Piraten",blue="AfD",grey="Sonstige",navy="Bundestagswahlen"), guide = "legend") +
   theme_bw() +
  theme(legend.position = "bottom") +
  theme(axis.text.x = element_text(angle = 90)) +
  labs(title="Forsa-Sonntagsfrage Bundestagswahl in %")+ylab("Prozent")+xlab("Jahre")

plot1

提前致谢

Answer 1

您的代码有很多不必要的重复，而且您没有利用 ggplot 的语法。

图例中出现垂直虚线的原因是您的一个 geom_vline 调用包含颜色映射，因此它的绘制键被添加到图例中。您可以将其 key_glyph 更改为 draw_key_path 来解决此问题。请注意，您只需要一个 geom_vline 调用，因为您可以有多个 x 截距。

ggplot(datacom, aes(x = Datum)) +
  geom_line(aes(y = `CDU/CSU`, colour = "black"), size = 0.8) +
  geom_line(aes(y = SPD, colour = "red"), size = 0.8) +
  geom_line(aes(y = GRÜNE, col = "green"), size = 0.8) +
  geom_line(aes(y = FDP, col = "gold1"), size = 0.8) +
  geom_line(aes(y = `Linke/PDS`, col = "darkred"),size = 0.8) +
  geom_line(aes(y = Piraten, col = "tan1"), 
            data = datacom[154:168,], size = 0.8) +
  geom_line(aes(y = AfD, col = "blue"),
            data = datacom[169:272,], size = 0.8) +
  geom_line(aes(y = Sonstige, col = "grey"), size = 0.8) +
  geom_vline(data = datacom[c(263, 215, 167, 127, 79, 44),],
             aes(xintercept = Datum, color = "navy"), linetype = "longdash", 
             size = 0.5, key_glyph = draw_key_path)+
  scale_color_identity(name = NULL, 
                       labels = c(black = "CDU/CSU", red = "SPD",
                                  green = "Die Grünen", gold1 = "FDP",
                                  darkred = "Die Linke/PDS",
                                  tan1 = "Piraten", blue = "AfD",
                                  grey = "Sonstige",
                                  navy = "Bundestagswahlen"),
                       guide = "legend") +
  theme_bw() +
  theme(legend.position = "bottom",
        axis.text.x     = element_text(angle = 90)) +
  labs(title = "Forsa-Sonntagsfrage Bundestagswahl in %",
       y     = "Prozent",
       x     = "Jahre")

制作绘图的更好方法是将数据转换为长格式。这意味着只有一个 geom_line 调用：

library(tidyverse)

datacom %>%
  mutate(Piraten = c(rep(NA, 153), Piraten[154:168], 
                     rep(NA, nrow(datacom) - 168)),
         AfD     = c(rep(NA, 168), AfD[169:272], 
                     rep(NA, nrow(datacom) - 272))) %>%
  pivot_longer(-Datum, names_to = "Series") %>%
  ggplot(aes(x = Datum, y = value, color = Series)) +
  geom_line(size = 0.8, na.rm = TRUE) +
  geom_vline(data = datacom[c(263, 215, 167, 127, 79, 44),],
             aes(xintercept = Datum, color = "Bundestagswahlen"), 
             linetype = "longdash", size = 0.5, key_glyph = draw_key_path) +
  scale_color_manual(name = NULL, 
                     values = c("CDU/CSU" = "black", SPD = "red",
                                "GRÜNE" = "green", FDP = "gold1",
                                "Linke/PDS" = "darkred",
                                Piraten = "tan1", AfD = "blue",
                                Sonstige = "grey",
                                "Bundestagswahlen" = "navy")) +
  theme_bw() +
  theme(legend.position = "bottom",
        axis.text.x     = element_text(angle = 90)) +
  labs(title = "Forsa-Sonntagsfrage Bundestagswahl in %",
       y     = "Prozent",
       x     = "Jahre")

用于创建绘图的数据

显然，我必须创建一些数据才能将您的代码发送到运行，因为您没有提供任何数据。这是我创建数据的代码

var <- seq(5, 15, length = 280)

datacom <- data.frame(Datum       = seq(as.POSIXct("1999-01-01"), 
                                        as.POSIXct("2022-04-01"), by = "month"),
                      `CDU/CSU`   = 40 + cumsum(rnorm(280)),
                      SPD         = 40 + cumsum(rnorm(280)),
                      GRÜNE       = rpois(280, var),
                      FDP         = rpois(280, var),
                      `Linke/PDS` = rpois(280, var),
                      Piraten     = rpois(280, var),
                      AfD         = rpois(280, var),
                      Sonstige    = rpois(280, var), check.names = FALSE)

ggplot2 scale_color_identity() 如何更改图例的线型和设计？

ggplot2 scale_color_identity() how to change linestyle and design of the legend?

r

ggplot2

legend