Moving x or y axis together with tick labels to the middle of a single ggplot (no facets)

问题

I made the following plot in Excel:

But then I thought I would make it prettier by using ggplot. I got this far:

If you're curious, the data is based on my answer here, although it doesn't really matter. The plot is a standard ggplot2 construct with some prettification, and the thick line for the x-axis through the middle is achieved with p + geom_hline(aes(yintercept=0)) (p is the ggplot object).

I feel that the axis configuration in the Excel plot is better. It emphasizes the 0 line (important when the data is money) and finding intercepts is much easier since you don't have to follow lines from all the way at the bottom. This is also how people draw axes when plotting on paper or boards.

Can the axis be moved like this in ggplot as well? I want not just the line, but the tick labels as well moved. If yes, how? If no, is the reason technical or by design? If by design, why was the decision made?

回答1:

try this,

shift_axis <- function(p, y=0){
  g <- ggplotGrob(p)
  dummy <- data.frame(y=y)
  ax <- g[["grobs"]][g$layout$name == "axis-b"][[1]]
  p + annotation_custom(grid::grobTree(ax, vp = grid::viewport(y=1, height=sum(ax$height))), 
                        ymax=y, ymin=y) +
    geom_hline(aes(yintercept=y), data = dummy) +
    theme(axis.text.x = element_blank(), 
          axis.ticks.x=element_blank())

}

p <- qplot(1:10, 1:10) + theme_bw() 
shift_axis(p, 5)

回答2:

I tried to change the theme's axis.text.x,but only can change hjust.
So I think you can delete axis.text.x,then use geom_text() to add.
For example:

test <- data.frame(x=seq(1,5), y=seq(-1,3))
ggplot(data=test, aes(x,y)) +
  geom_line() +
  theme(axis.text.x=element_blank(), axis.ticks.x=element_blank()) +
  geom_text(data=data.frame(x=seq(1,5), y=rep(0,5)), label=seq(1,5), vjust=1.5)

Maybe these codes are useful.

回答3:

just to complete baptiste's excellent answer with the equivalent for moving the y axis:

shift_axis_x <- function(p, x=0){
      g <- ggplotGrob(p)
      dummy <- data.frame(x=x)
      ax <- g[["grobs"]][g$layout$name == "axis-l"][[1]]
      p + annotation_custom(grid::grobTree(ax, vp = grid::viewport(x=1, width = sum(ax$height))), 
                            xmax=x, xmin=x) +
        geom_vline(aes(xintercept=x), data = dummy) +
        theme(axis.text.y = element_blank(), 
              axis.ticks.y=element_blank())
    }

回答4:

As alistaire commented it can be done using geom_hline and geom_text as shown below.

df <- data.frame(YearMonth = c(200606,200606,200608,200701,200703,200605),
             person1 = c('Alice','Bob','Alice','Alice','Bob','Alice'),
             person2 = c('Bob','Alice','Bob','Bob','Alice','Bob'),
             Event = c('event1','event2','event3','event3','event2','event4')
)

df$YM <- as.Date(paste0("01",df$YearMonth), format="%d%Y%m")
rangeYM <- range(df$YM)

ggplot()+geom_blank(aes(x= rangeYM, y = c(-1,1))) + labs(x = "", y = "") +
theme(axis.ticks = element_blank()) +
geom_hline(yintercept = 0, col = 'maroon') +
scale_x_date(date_labels = '%b-%y', date_breaks = "month", minor_breaks = NULL) +
scale_y_continuous(minor_breaks = NULL) +
geom_text(aes(x = df$YM, y = 0, label = paste(format(df$YM, "%b-%y")), vjust = 1.5), colour = "#5B7FA3", size = 3.5, fontface = "bold")

来源：https://stackoverflow.com/questions/39071002/moving-x-or-y-axis-together-with-tick-labels-to-the-middle-of-a-single-ggplot-n

标签

plot

ggplot2

axes