r - 如何仅更改图例中的几何绘图顺序？

Question

我正在 ggplot2 中绘制一个包含 geom_pointrange 和 geom_line 的图。我看到当我改变几何的顺序时，点要么被绘制在线条的顶部，反之亦然。图例还会根据几何体的相同顺序更改绘制在另一个几何体之上的几何体。但是，我希望先绘制线条，然后绘制顶部的点范围，在情节本身中，在图例中进行相反的绘制。这可能吗？我将不胜感激任何输入。

这是我用来制作图形的代码。

md.figd2 <- structure(list(date = c("2013-05-28", "2013-07-11", "2013-09-22", 
"2013-05-28", "2013-07-11", "2013-09-22", "2013-05-28", "2013-07-11", 
"2013-09-22"), trt = structure(c(3L, 3L, 3L, 1L, 1L, 1L, 2L, 
2L, 2L), .Label = c("- Fescue", "- Random", "Control"), class = "factor"), 
means = c(1, 0.921865257043089, 0.793438250521971, 1, 0.878305313846414, 
0.85698797555687, 1, 0.840679145697309, 0.798547331410388
), mins = c(1, 0.87709562979756, 0.72278951032918, 1, 0.816185624483356, 
0.763720265496049, 1, 0.780804129401513, 0.717089626439849
), maxes = c(1, 0.966634884288619, 0.864086990714762, 1, 
0.940425003209472, 0.950255685617691, 1, 0.900554161993105, 
0.880005036380927)), .Names = c("date", "trt", "means", "mins", 
"maxes"), row.names = c(NA, 9L), class = "data.frame")

library(ggplot2)
dplot1.ysc <- scale_y_continuous(limits=c(0,1), breaks=seq(0,1,.2), name='Proportion mass lost')
dplot1.xsc <- scale_x_date(limits=as.Date(c('2013-05-23', '2013-10-03')), labels=c('May 28', 'July 11', 'Sep 22'), breaks=md.figdata$date, name='Date')
dplot1.csc <- scale_color_manual(values=c('grey20','grey50','grey80'))
dplot1.lsc <- scale_linetype_manual(values=c('solid','dotted','dashed'))
djitter <- rep(c(0,-1,1), each=3)

# This one produces the plot with the legend I want.
dplot1b <- ggplot(md.figd2, aes(x=date + djitter, y=means, group=trt)) + geom_pointrange(aes(ymin=mins, ymax=maxes, color=trt), size=2) + geom_line(aes(linetype=trt), size=1)
# This one produces the plot with the points on the main plot that I want.
dplot1b <- ggplot(md.figd2, aes(x=date + djitter, y=means, group=trt)) + geom_line(aes(linetype=trt), size=1) + geom_pointrange(aes(ymin=mins, ymax=maxes, color=trt), size=2)

dplot1b + dplot1.xsc + dplot1.ysc + dplot1.csc + dplot1.lsc

Answer 1

您可以使用 gtable::gtable_filter从您想要的图中提取图例，然后 gridExtra::grid.arrange重新创建你想要的情节

# the legend I want
plot1a <- ggplot(md.figd2, aes(x=date , y=means, group=trt)) + 
  geom_pointrange(aes(ymin=mins, ymax=maxes, color=trt), size=2, 
                      position = position_dodge(width=1)) + 
  geom_line(aes(linetype=trt), size=1)
# This one produces the plot with the points on the main plot that I want.
dplot1b <- ggplot(md.figd2, aes(x=date, y=means, group=trt)) + 
  geom_line(aes(linetype=trt), size=1) + 
  geom_pointrange(aes(ymin=mins, ymax=maxes, color=trt), size=2)

w <- dplot1b + dplot1.xsc + dplot1.ysc + dplot1.csc + dplot1.lsc
# legend
l <- dplot1a + dplot1.xsc + dplot1.ysc + dplot1.csc + dplot1.lsc

library(gtable)
library(gridExtra)
# extract legend ("guide-box" element)
leg <- gtable_filter(ggplot_gtable(ggplot_build(l)), 'guide-box')
# plot the two components, adjusting the widths as you see fit.
grid.arrange(w + theme(legend.position='none'),leg,ncol=2, widths = c(3,1))

另一种方法是简单地用您想要提取的图例替换您想要的图中的图例(使用 gtable_filter )

# create ggplotGrob of plot you want
wGrob <- ggplotGrob(w)
# replace the legend
wGrob$grobs[wGrob$layout$name == "guide-box"][[1]] <- leg
grid.draw(wGrob)