我如何使用ggplot2添加背景网格？ [英] How can I add a background grid using ggplot2?

问题描述

我想将背景网格添加到图的中心，然后隐藏标准网格线。网格的角点存储在pts数据框中，我尝试过使用geom_tile，但它似乎没有使用指定的点。

I'd like to add background grid to the center of the plot and then hide the standard gridlines. The corner points of the grid are stored in the pts data frame and I've tried using geom_tile, but it doesn't appear to use the specified points. Thanks in advance for your help.

library(ggplot2)  
pts <- data.frame(
        x=c(170,170,170,177.5,177.5,177.5,185,185,185), 
        y=c(-35,-25,-15,-35,-25,-15,-35,-25,-15))  
ggplot(quakes, aes(long, lat)) + 
    geom_point(shape = 1) + 
    geom_tile(data=pts,aes(x=x,y=y),fill="transparent",colour="black") +
    opts(
        panel.grid.major=theme_blank(),
        panel.grid.minor=theme_blank()
    )

推荐答案

您可以手动指定中断：

ggplot(quakes, aes(long, lat)) + geom_point(shape = 1) +
  scale_x_continuous(breaks = c(170, 177.5, 185)) +
  scale_y_continuous(breaks = c(-35, -25, -15)) +
  opts(panel.grid.minor = theme_blank(), 
       panel.grid.major = theme_line("black", size = 0.1))

然后，这是你想要的吗？

then, is this what you want?

pts <- data.frame(x=c(170, 170, 170, 170, 177.5, 185), 
                  y=c(-35, -25, -15, -35, -35, -35),
                  xend=c(185, 185, 185, 170, 177.5, 185),
                  yend=c(-35, -25, -15, -15, -15, -15))
ggplot(quakes, aes(long, lat)) + geom_point(shape = 1) + 
   geom_segment(data=pts, aes(x, y, xend=xend, yend=yend)) +
   opts(panel.grid.minor = theme_blank(), 
        panel.grid.major = theme_blank())

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