如何在 R 中使用 ggplot 绘制绘图区域的“外部”?

时间:2021-02-21 20:51:32

标签: r ggplot2

我最近问了 this 个问题。但是,我现在提出一个单独的问题,因为我的新问题的范围超出了上一个问题的范围。

我正在尝试在 ggplot 中创建一个热图……但是,在轴之外我正在尝试绘制 geom_tile。问题是我找不到一致的方法来让它工作。例如,我用来绘制的代码是:

library(colorspace)
library(ggplot2)
library(ggnewscale)
library(tidyverse)

asd <- expand_grid(paste0("a", 1:9), paste0("b", 1:9))

df <- data.frame(
  a = asd$`paste0("a", 1:9)`,
  b = asd$`paste0("b", 1:9)`,
  c = sample(20, 81, replace = T)
)


# From discrete to continuous
df$a <- match(df$a, sort(unique(df$a)))
df$b <- match(df$b, sort(unique(df$b)))
z <- sample(10, 18, T)


# set color palettes
pal <- rev(diverging_hcl(palette = "Blue-Red", n = 11))
palEdge <- rev(sequential_hcl(palette = "Plasma", n = 11))

# plot
ggplot(df, aes(a, b)) +
  geom_tile(aes(fill = c)) +
  scale_fill_gradientn(
    colors = pal,
    guide = guide_colorbar(
      frame.colour = "black",
      ticks.colour = "black"
    ),
    name = "C"
  ) +
  theme_classic() +
  labs(x = "A axis", y = "B axis") +
  new_scale_fill() +
  geom_tile(data = tibble(a = 1:9, 
                          z = z[1:9]),
            aes(x = a, y = 0, fill = z, height = 0.3)) +
  geom_tile(data = tibble(b = 1:9, 
                          z = z[10:18]),
            aes(x = 0, y = b, fill = z, width = 0.3))  +
  scale_fill_gradientn(
    colors = palEdge,
    guide = guide_colorbar(
      frame.colour = "black",
      ticks.colour = "black"
    ),
    name = "Z"
  )+
  coord_cartesian(clip = "off", xlim = c(0.5, NA), ylim = c(0.5, NA)) +
  theme(aspect.ratio = 1,
        plot.margin = margin(10, 15.5, 25, 25, "pt")
  )

这会产生这样的结果: heatmap

然而,我试图找到一种一致的方式来绘制更像这样的东西(我很快在photoshop中制作了它): heatmap with tiles outside

我遇到的主要问题是能够在绘图区域“外部”操纵新比例尺的坐标。有没有办法移动外面的瓷砖,以便我可以将它们放置在有意义的区域?

1 个答案:

答案 0 :(得分:6)

在绘图区域外绘图时总是有两个经典选项:

  • coord_...(clip = "off") 注释/绘图
  • 制作不同的图并将它们组合起来。

在我看来,后一种选择通常提供更大的灵活性和更少的麻烦。

library(colorspace)
library(tidyverse)
library(patchwork)

asd <- expand_grid(paste0("a", 1:9), paste0("b", 1:9))

df <- data.frame(
  a = asd$`paste0("a", 1:9)`,
  b = asd$`paste0("b", 1:9)`,
  c = sample(20, 81, replace = T)
)


# From discrete to continuous
df$a <- match(df$a, sort(unique(df$a)))
df$b <- match(df$b, sort(unique(df$b)))
z <- sample(10, 18, T)


# set color palettes
pal <- rev(diverging_hcl(palette = "Blue-Red", n = 11))
palEdge <- rev(sequential_hcl(palette = "Plasma", n = 11))

# plot
p_main <- ggplot(df, aes(a, b)) +
  geom_tile(aes(fill = c)) +
  scale_fill_gradientn("C",colors = pal,
    guide = guide_colorbar(frame.colour = "black",
      ticks.colour = "black")) +
  theme_classic() +
  labs(x = "A axis", y = "B axis") 
p_bottom <- ggplot() +
  geom_tile(data = tibble(a = 1:9, z = z[1:9]),
            aes(x = a, y = 0, fill = z, height = 0.3)) +
  theme_void() +
  scale_fill_gradientn("Z",limits = c(0,10),
                       colors = palEdge,
                       guide = guide_colorbar( 
                         frame.colour = "black", ticks.colour = "black"))
p_left <- ggplot() +
  theme_void()+
  geom_tile(data = tibble(b = 1:9, z = z[10:18]),
            aes(x = 0, y = b, fill = z, width = 0.3))  +
  scale_fill_gradientn("Z",limits = c(0,10),
    colors = palEdge,
    guide = guide_colorbar( frame.colour = "black", ticks.colour = "black"))

p_left + p_main +plot_spacer()+ p_bottom +
  plot_layout(guides = "collect",
              heights = c(1, .1),
              widths = c(.1, 1)) 

reprex package (v1.0.0) 于 2021 年 2 月 21 日创建

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