更改ggplot中线的覆盖顺序

问题描述

假设我有这个情节:

library(ggplot2)
pl_data <- data.frame(x = rep(c(1, 2), times = 3), y = c(0, 1, 1, 0, .7, .7), col = rep(c("r", "b", "g"), each = 2))
ggplot(pl_data, aes(x = x, y = y, color = col)) +
  geom_line(size = 3)

如何更改打印顺序，以便红线排在其他两个上方?

How can I change the plotting order, so that the red lineis plotted above the other two?

因此，背景是我的情节非常相似行，并希望在前景中看到特定的行.

The background therefore is that I have plots with very similarlines, and want to see specific lines in the foreground.

我猜想与此答案类似的内容 ggplot中堆积条形的顺序会工作.它使颜色列受因素影响并更改其顺序，但我希望更改这直接在ggplot调用的一行中.

I suppose something along the lines of this answer order of stacked bars in ggplot would work. It makes the color column to factors and changes their order, but I would prefer to changethis directly in a line of the ggplot call.

我还尝试使用scale_color_discrete(breaks=c("r", "g", "b"))更改图例顺序，但这也不影响打印顺序.

I also tried changing the legend order with scale_color_discrete(breaks=c("r", "g", "b"))),but that does not effect the plotting order either.

推荐答案

因此，实际上col的最后一层位于顶部.因此，您需要更改因子的顺序并反转颜色，因为红色会自动映射到第一级(使用标准颜色来说明问题):

So actually the last level of col is on the top. So you need to change the order of the factor and reverse the colors as red is automatically mapped to the first level (used standard colors to illustrate the problem):

pl_data$col <- factor(pl_data$col, c("r", "g", "b"))
ggplot(pl_data, aes(x = x, y = y, color = col)) +
    geom_line(size = 3) +
    scale_color_manual(values = c(r = "blue", g = "green", b = "red"))

## with standard colors of ggplot2, function taken from:
## http://stackoverflow.com/questions/8197559/emulate-ggplot2-default-color-palette

ggplotColours <- function(n = 6, h = c(0, 360) + 15) {
  if ((diff(h) %% 360) < 1) h[2] <- h[2] - 360/n
  hcl(h = (seq(h[1], h[2], length = n)), c = 100, l = 65)
}
pal <- setNames(ggplotColours(3), c("b", "g", "r"))
ggplot(pl_data, aes(x = x, y = y, color = col)) +
    geom_line(size = 3) +
    scale_color_manual(values = pal, breaks = c("b", "g", "r"))

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