Putting x-axis at top of ggplot2 chart

I feel like this should be obvious... all I'm trying to do is to remove the x-axis from the bottom of my graph and add it to the top.

Here is a reproducible example. Data plus code to make the following graph:

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) )

enter image description here

But what I'm trying to produce is- it seems like this should be obvious (e.g. it's very easy to do in base-R) , but I haven't managed to find what I'm looking for in ggplot2.

enter image description here

64449 次浏览
小开

I've used this work around. Used a duplicated the plot's x-axis and affixed the two together, then crop. I don't have the cleaned up code, but below is an example. 

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)

enter image description here

小开

check out the cowplot package

ggdraw(switch_axis_position(p + axis = 'x'))
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最佳答案

You can move the x-axis labels to the top by adding 

scale_x_discrete(position = "top")
小开

see http://ggplot2.tidyverse.org/reference/sec_axis.html 

scale_y_continuous(sec.axis = dup_axis())
小开

Nowadays, you can do this by adding "position = 'top'" in the scale_x_discrete.

code:

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),position = 'top') +
scale_y_discrete(expand = c(0, 0),position = 'left') +
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) )

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