联合ggplot中的传奇位置

时间:2016-09-29 20:15:29

标签: r ggplot2 legend

我是R的新手,更不用说ggplot了,所以我提前为下面的例子中的任何问题道歉。

使用现有问题中的示例,我尝试将代码组合在一起以组合两个单独的ggplots。我想知道如何将最终绘图的图例移动到图表上方。我试过将legend.postion更改为" top"对于个人ggplots,但它似乎不起作用。

(请注意,我已经省略了第二个y轴的创建,以便将示例中的代码保持在我认为需要的最小值来说明我的问题)

    library(ggplot2)
    library(gtable)
    library(reshape2)
    library(grid)
    library(scales)

    df.test <- data.frame(
        x_cat = factor(c(1, 2, 3, 4)),
        count = seq(1:4),
        line1 = seq(from = 1, to = 4, length.out = 4),
        line2 = seq(from = 0, to = 3, length.out = 4)
    )

    p1 <- ggplot( data = df.test , aes(x=x_cat, y=count) ) +
          geom_bar( stat="identity" ) +
          xlab( "X Label" ) +
          ylab( "Y Label 1" ) +
          theme(panel.background = element_rect(colour = "white"),
                panel.grid.major = element_blank(),
                panel.grid.minor = element_blank(),
                legend.position = "bottom")
    g1 <- ggplotGrob( p1 )

    df.test2 <- melt( df.test[-2] )
    p2 <- ggplot( data = df.test2 , aes(x=x_cat, y=value, colour=variable ) ) +
          geom_line( aes(group=variable) ) +
          ylab( "Y Label 2" ) +
          theme(panel.background = element_rect(fill = NA, colour = "white"),
                panel.grid.major = element_blank(),
                panel.grid.minor = element_blank(),
                legend.position = "bottom") 
    g2 <- ggplotGrob(p2)

    pp <- c(subset(g1$layout, name == "panel", se = t:r))
    g <- gtable_add_grob(g1, g2$grobs[[which(g2$layout$name == "panel")]], pp$t, pp$l, pp$b, pp$l)

    pp <- c(subset(g2$layout, name == "guide-box", se = t:r))
    g <- gtable_add_grob(g, g2$grobs[[which(g2$layout$name == "guide-box")]], t=pp$t, l=pp$l, b=pp$b, r=pp$r)

    grid.draw(g)

1 个答案:

答案 0 :(得分:2)

您不需要将两个单独的图组合在一起。 ggplot方法是将其视为具有两个层的单个图,即条形图层和线条图层。所以我们只需要弄清楚如何将这些图层放在一个图上。例如:

library(ggplot2)
library(reshape2)

df.test <- data.frame(
  x_cat = factor(c(1, 2, 3, 4)),
  count = seq(1:4),
  line1 = seq(from = 1, to = 4, length.out = 4),
  line2 = seq(from = 0, to = 3, length.out = 4)
)

df.test2 = melt(df.test, id.var=c("x_cat", "count"))

ggplot() +
  geom_bar(data=subset(df.test2, variable=="line1"), aes(x=x_cat, y=count), 
           stat="identity" ) +
  geom_line(data=df.test2, aes(x=x_cat, y=value, colour=variable, group=variable)) +
  xlab( "X Label" ) +
  ylab( "Y Label 1" ) +
  theme(panel.background = element_rect(colour = "white"),
        panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(),
        legend.position = "top")

enter image description here

事实证明,我们在这里并不需要任何传奇体操。但是,如果您确实需要将单独的图表与单个图例组合在一起,hereherehere就是一些例子。