Question

问题是：geom_rect使用ggplot2防止facet_grid的缩放。

我想知道它是否是由两个数据帧中的冲突引起的，但不知道如何解决此问题。希望您能够帮助我。

示例代码如下：

library(ggplot2)
data_1 <- data.frame(x = c(seq(from = 1, to = 10, by = 1),
                           seq(from = 21, to = 50, by = 1)),
                     y = rnorm(40, mean = 3, sd = 1),
                     z = c(rep("A", 10), rep("B", 30)))

shade <- 
  data.frame(xmin = c(2, 6, 39),
             xmax = c(3, 8, 43),
             ymin = - Inf,
             ymax = Inf)

如果不使用geom_rect，我可以像这样适当地使用facet_grid进行缩放：

ggplot(data = data_1, aes(x = x, y = y)) +
  geom_bar(stat = "identity", fill = "blue") +
  facet_grid(.~z, space = "free_x", scales = "free_x")

结果是这样的：

但是，如果我绘制一些geom_rect，则先前显示的比例将消失，并带有如下代码和图形：

ggplot(data = data_1, aes(x = x, y = y)) +
  geom_bar(stat = "identity", fill = "blue") +
  geom_rect(data = shade, inherit.aes = FALSE,
            mapping = aes(xmin = xmin, 
                          xmax = xmax, 
                          ymin = ymin, ymax = ymax),
            fill = 'red', alpha = 0.2) +
  facet_grid(.~z, space = "free_x", scales = "free_x")

在绘制这些geom_rect时如何保持先前在x上的缩放比例？

任何建议都将不胜感激。

Answer 1

x轴范围发生变化，因为geom_rect层中的数据超出了原始图的范围。秤的功能完全符合预期。

如果要为每个构面显示不同的矩形，将构面变量包含在shade中会更干净，并且仅保留xmin / xmax 在每个方面的范围内。例如：

library(dplyr) shade2 <- shade %>% # add facet-specific x-axis range information from data_1 tidyr::crossing(data_1 %>% group_by(z) %>% summarise(x1 = min(x), x2 = max(x)) %>% ungroup) %>% # filter for rects within each facet's x-axis range group_by(z) %>% filter(xmin >= x1 & xmax <= x2) %>% ungroup() > shade2 # A tibble: 3 x 7 xmin xmax ymin ymax z x1 x2 <dbl> <dbl> <dbl> <dbl> <fct> <dbl> <dbl> 1 2 3 -Inf Inf A 1 10 2 6 8 -Inf Inf A 1 10 3 39 43 -Inf Inf B 21 50

图：

ggplot(data = data_1, aes(x = x, y = y)) + geom_col(fill = "blue") + # geom_col is equivalent to geom_bar(stat = "identity") geom_rect(data = shade2, inherit.aes = FALSE, mapping = aes(xmin = xmin, xmax = xmax, ymin = ymin, ymax = ymax), fill = 'red', alpha = 0.2) + facet_grid(.~z, space = "free_x", scales = "free_x")

ggplot2 geom_rect在facet_grid下无法适当缩放

1 个答案: