r（ggplot2 折线图）：更改错误栏的线型会在图例中更改它们

Question

我有一个这样的折线图：

df <- data.frame(x = c(1,1,2,2,1,1,2,2), 
  y = c(1.5,1.9,2.1,1.6,1.4,1.8,2.0,1.7), 
  error = c(0.2), 
  group = c("g1","g2","g1","g2","g3","g4","g3","g4"))

ggplot(df, aes(x = x, y = y, color = group, linetype = group)) + 
  geom_point() + geom_line() + 
  geom_errorbar(aes(ymin = y - error, ymax = y + error),
                linetype = 1, width = 0.5,                                 
                position = position_dodge(width = 0.2)) +
  scale_color_manual(values = c("g1"="Black", "g2"="Grey", "g3"="Black", "g4"="Grey")) +
  scale_linetype_manual(values=c("g1"=1,"g2"=1,"g3"=2,"g4"=2))

我需要把它变成黑白的，所以对于几个组，我同时使用了 color 和 linetype。当我更改线型时，尽管线条是虚线，但我希望误差线是实心的，所以我覆盖了误差线的线型。由于某些原因，这也更改了图例，因此不再清楚哪条线是哪条线。

我知道这在某种程度上取决于 aes 中的 color = group，因为当我只有线型时，图例很好。出于某种原因，我就是找不到同时处理线型、颜色和实体错误栏的方法。有人知道这是为什么吗？

Answer 1

试试这个：

    ggplot(df, aes(x = x, y = y, colour = group, group = group)) + 
  geom_line(aes(y=y,linetype = group)) +
  geom_point()+
  geom_errorbar(aes(ymin = y - error, ymax = y + error),
                colour = rep(c("black","grey"),4),
                width = 0.1,                                 
                position = "dodge") +
  scale_color_manual(values = c("g1"="Black", "g2"="Grey", "g3"="Black", "g4"="Grey")) +
  scale_linetype_manual(values=c("g1"=1,"g2"=1,"g3"=2,"g4"=2))

您不需要 ggplot 中的 linetype = group，因为误差线永远不会使用此信息。你只是让它变得更复杂。线型将仅由线条和图例使用。错误栏需要知道颜色和分组变量，这就是为什么将它们包含在 ggplot 中。

通过创建列设置颜色：

df <- data.frame(x = c(1,1,2,2,1,1,2,2), 
                 y = c(1.5,1.9,2.1,1.6,1.4,1.8,2.0,1.7), 
                 error = c(0.2), 
                 group = c("g1","g2","g1","g2","g3","g4","g3","g4"))


df$group_cols = "black"
df$group_cols[df$group %in% c("g2","g4")] = "grey"


ggplot(df, aes(x = x, y = y, colour = group, group = group)) + 
  geom_line(aes(y=y,linetype = group)) +
  geom_point()+
  geom_errorbar(aes(ymin = y - error, ymax = y + error),
                colour = df$group_cols,
                width = 0.1,                                 
                position = "dodge") +
  scale_color_manual(values = c("g1"="Black", "g2"="Grey", "g3"="Black", "g4"="Grey")) +
  scale_linetype_manual(values=c("g1"=1,"g2"=1,"g3"=2,"g4"=2))

r（ggplot2 折线图）：更改错误栏的线型会在图例中更改它们

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