如何用ggplot2将IPCC点画添加到全局地图中

Question

我需要将IPCC(-style)的点画添加到全球地图中，就像在这个职位中一样。但是，我想使用ggplot2的一个功能来完成这个任务。

这里是一个数据和绘图的例子：

test.csv

df=read.csv("/home/my_folder/test.csv")

library(ggplot2)
library(metR)

plot_df = ggplot() +
  geom_contour_fill(data=df, aes(x=V1, y=V2, z = value)) +
  scale_fill_steps2(name = "", low = "#0571b0", mid = '#ffffbf', high = '#ca0020')

print(plot_df)

​

​

我如何在这张图片中添加IPCC点画？

我试过使用geom_point()，但是点画太大了，掩盖了背景色。

谢谢

编辑

在@Allan回答之后，我确实可以添加以下点画：

library(ggplot2)
library(ggpattern)

df=read.csv("~/...../test.csv")

df_stippl=df[c(10:47, 100:250, 500:510, 707:1000, 1508:1699, 2500:2600, 2680:2690, 3400:4300),]

plot_df = ggplot() +
  
  geom_contour_fill(data=df, aes(x=V1, y=V2, z = value)) +
  
  stat_contour_fill(data=df_stippl, aes(x=V1, y=V2, z = value), geom = "polygon_pattern", 
                    pattern_fill = "black", pattern_size = 0,
                    pattern = "crosshatch", pattern_spacing = 0.02,
                    pattern_angle = 45, pattern_density = 0.1) +
  
  scale_fill_steps2(name = "", low = "#0571b0", mid = '#ffffbf', high = '#ca0020')

print(plot_df)

​

​

然而，当我以pdf格式保存这个数字时：

pdf('~/...../figure.pdf', width = 10, height = 6.6)
print(plot_df)
dev.off()

我在全球各地都得到了完整的点画，而不仅仅是在df_stippl地区。

Answer 1

你可以用几种方法。也许最简单的方法是获取覆盖数据的六边形网格的中心点，然后用geom_point绘制。

library(ggplot2)
library(metR)
library(hexbin)

df = read.csv("../test.csv")

hb  <- erode(hexbin(df$V1, df$V2, xbins = 55))
df2 <- as.data.frame(hcell2xy(hb))

ggplot() +
  geom_contour_fill(data=df, aes(x=V1, y=V2, z = value)) +
  scale_fill_steps2(name = "", low = "#0571b0",
                    mid = '#ffffbf', high = '#ca0020') +
  geom_point(data = df2, aes(x, y), color = "black", size = 1) +
  theme_bw() 

​

​

如果您希望点具有不同的密度，则可以更改xbins。

hb  <- erode(hexbin(df$V1, df$V2, xbins = 20))
df2 <- as.data.frame(hcell2xy(hb))

ggplot() +
  geom_contour_fill(data=df, aes(x=V1, y=V2, z = value)) +
  scale_fill_steps2(name = "", low = "#0571b0",
                    mid = '#ffffbf', high = '#ca0020') +
  geom_point(data = df2, aes(x, y), color = "black", size = 1) +
  theme_bw() 

​

​

另一种方法是过滤掉数据帧中的一些行，并在其中绘制点：

ggplot(df, aes(V1, V2)) +
  geom_contour_fill(aes(z = value)) +
  geom_point(data = df[(df$V1 + df$V2) %% 3 == 0,], color = "black", size = 1) +
  scale_fill_steps2(name = "", low = "#0571b0", 
                    mid = '#ffffbf', high = '#ca0020') +
  theme_bw() 

​

​

将所有这些与仅仅标出要点进行比较：

ggplot(df, aes(V1, V2)) +
  geom_contour_fill(aes(z = value)) +
  geom_point(color = "black", size = 1) +
  scale_fill_steps2(name = "", low = "#0571b0", 
                    mid = '#ffffbf', high = '#ca0020') +
  theme_bw() 

​

​

编辑

如果你想要交叉孵化，你可以：

library(ggplot2)
library(metR)
library(ggpattern)

df <- read.csv("../test.csv")

ggplot(df, aes(V1, V2)) +
  stat_contour_fill(aes(z = value), geom = "polygon_pattern", 
                      pattern_fill = "black", pattern_size = 0,
                      pattern = "crosshatch", pattern_spacing = 0.02,
                      pattern_angle = 45, pattern_density = 0.1) +
  scale_fill_steps2(name = "", low = "#0571b0", mid = '#ffffbf',
                    high = '#ca0020') +
  theme_bw() 

​

​

若要将绘图保存为pdf格式，您需要使用cairo_pdf。

df_stippl=df[c(10:47, 100:250, 500:510, 707:1000, 1508:1699, 
               2500:2600, 2680:2690, 3400:4300),]

plot_df = ggplot() +
  geom_contour_fill(data=df, aes(x=V1, y=V2, z = value)) +
  stat_contour_fill(data=df_stippl, aes(x=V1, y=V2, z = value), 
                    geom = "polygon_pattern", 
                    pattern_fill = "black", pattern_size = 0,
                    pattern = "crosshatch", pattern_spacing = 0.02,
                    pattern_angle = 45, pattern_density = 0.1) +
  scale_fill_steps2(name = "", low = "#0571b0", mid = '#ffffbf', 
                    high = '#ca0020')

cairo_pdf('../figure.pdf', width = 10, height = 6.6)
print(plot_df)
dev.off()

figure.pdf

​

​