将x轴放在ggplot2图表的顶部

Question

我觉得这应该是显而易见的......我所要做的就是从图形底部删除x轴并将其添加到顶部.

这是一个可重复的例子.数据加代码来制作以下图表:

library(reshape2)
library(ggplot2)

data(mtcars)
dat <- with(mtcars, data.frame(mpg, cyl, disp, hp, wt, gear))
cor.matrix <- round(cor(dat, use = "pairwise.complete.obs", method = "spearman"), digits = 2)
diag(cor.matrix)<-NA

cor.dat <- melt(cor.matrix)
cor.dat <- data.frame(cor.dat)
cor.dat <- cor.dat[complete.cases(cor.dat),]


ggplot(cor.dat, aes(Var2, Var1, fill = value)) + 
  geom_tile(colour="gray90", size=1.5, stat="identity") + 
  geom_text(data=cor.dat, aes(Var2, Var1, label = value), color="black", size=rel(4.5)) +
  scale_fill_gradient(low = "white", high = "dodgerblue", space = "Lab", na.value = "gray90", guide = "colourbar") +
  scale_x_discrete(expand = c(0, 0)) +
  scale_y_discrete(expand = c(0, 0)) +
  xlab("") + 
  ylab("") +
  theme(panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(),
        panel.border = element_rect(fill=NA,color="gray90", size=0.5, linetype="solid"),
        axis.line = element_blank(),
        axis.ticks = element_blank(),
        panel.background = element_rect(fill="gray90"),
        plot.background = element_rect(fill="gray90"),
        legend.position = "none", 
        axis.text = element_text(color="black", size=14) )

但是我想要产生的是 - 它似乎应该是显而易见的(例如在base-R中很容易做到),但我还没有设法找到我在ggplot2中寻找的东西.

Answer 1

您可以通过添加将x轴标签移动到顶部

scale_x_discrete(position = "top") 

Answer 2

我已经用过这个工作了.使用复制图的x轴并将两者粘在一起,然后裁剪.我没有清理过的代码,但下面是一个例子.

p.bot   <-  
ggplot(cor.dat, aes(Var2, Var1, fill = value)) + 
  geom_tile(colour="gray90", size=1.5, stat="identity") + 
  geom_text(data=cor.dat, aes(Var2, Var1, label = value), color="black", size=rel(4.5)) +
  scale_fill_gradient(low = "white", high = "dodgerblue", space = "Lab", na.value = "gray90", guide = "colourbar") +
  scale_x_discrete(expand = c(0, 0)) +
  scale_y_discrete(expand = c(0, 0)) +
  xlab("") + 
  ylab("") +
  theme(panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(),
        panel.border = element_rect(fill=NA,color="gray90", size=0.5, linetype="solid"),
        axis.line = element_blank(),
        axis.ticks = element_blank(),
        panel.background = element_rect(fill="gray90"),
        plot.background = element_rect(fill="gray90"),
        legend.position = "none", 
        axis.text.x = element_blank(),
        plot.margin = unit(c(1,0,0,0), "cm"),
        axis.text.y = element_text(color="black", size=14) )

p.top   <-  p.bot + theme(
    axis.text.x = element_text(color="black", size=14),
    axis.text.y = element_text(color="gray90", size=14)
    )  + coord_cartesian(ylim = c(0,0))



require(gtable)
#Extract Grobs
g1<-ggplotGrob(p.top)
g2<-ggplotGrob(p.bot)
#Bind the tables
g<-gtable:::rbind_gtable(g1, g2, "first")
#Remove a row between the plots
g <- gtable_add_rows(g, unit(-1.25,"cm"), pos=nrow(g1))
#draw
panels <- g$layout$t[grep("panel", g$layout$name)]
g$heights[panels] <- lapply(c(0,2), unit, "null")

grid.newpage()
grid.draw(g)

Answer 3

查看牛皮包

ggdraw(switch_axis_position(p + axis = 'x'))