如何在R中组合两个地图？

Question

我需要你的帮助，我提供了下面的示例代码。我的问题涉及将“map2”放置在“map1”左上角的正方形中，并添加从“map2”到“map1”上特定位置的箭头。我搜索过该网站，但最常讨论的主题与合并两个数据层有关。

如果您能帮助我，我将不胜感激。

library (tidyverse)
 library (rnaturalearth)
 world <- rnaturalearth::ne_countries(scale = "medium", returnclass = "sf")
 
 map1<- ggplot(data = world) +
   geom_sf() +
   #annotation_scale(location = "bl", width_hint = 0.2) +
   #annotation_north_arrow(location = "tr", which_north = "true", 
   #                     pad_x = unit(0.83, "in"), pad_y = unit(0.02, "in"),
   #                   style = north_arrow_fancy_orienteering) +
   coord_sf(xlim = c(35, 48), ylim=c(12, 22))+
   xlab("Longtitude")+
   ylab("Latitude")
 
  

 map2<- ggplot(data = world) +
   geom_sf() +
   #annotation_scale(location = "bl", width_hint = 0.2) +
   #annotation_north_arrow(location = "tr", which_north = "true", 
   #                     pad_x = unit(0.83, "in"), pad_y = unit(0.02, "in"),
   #                   style = north_arrow_fancy_orienteering) +
   coord_sf(xlim = c(5, 45), ylim=c(5, 45))+
   xlab("Longtitude")+
   ylab("Latitude")

 map2 

Answer 1

您可以使用令人惊叹的包

patchwork

来做到这一点，它有一个功能

inset_element()

。请注意，我稍微更改了

map2

的主题以删除所有轴刻度和标签，但您不必这样做：

library (tidyverse)
library (rnaturalearth)
library(patchwork)

world <- rnaturalearth::ne_countries(scale = "medium", returnclass = "sf")

map1<- ggplot(data = world) +
  geom_sf() +
  #annotation_scale(location = "bl", width_hint = 0.2) +
  #annotation_north_arrow(location = "tr", which_north = "true", 
  #                     pad_x = unit(0.83, "in"), pad_y = unit(0.02, "in"),
  #                   style = north_arrow_fancy_orienteering) +
  coord_sf(xlim = c(35, 48), ylim=c(12, 22))+
  xlab("Longtitude")+
  ylab("Latitude")



map2<- ggplot(data = world) +
  geom_sf() +
  #annotation_scale(location = "bl", width_hint = 0.2) +
  #annotation_north_arrow(location = "tr", which_north = "true", 
  #                     pad_x = unit(0.83, "in"), pad_y = unit(0.02, "in"),
  #                   style = north_arrow_fancy_orienteering) +
  coord_sf(xlim = c(5, 45), ylim=c(5, 45))+
  xlab("Longtitude")+
  ylab("Latitude") +
  theme_void() +
  theme(
    panel.border = element_rect(color = "black", fill = "transparent")
  )

map1 + inset_element(map2, left = 0.05, bottom = 0.6, right = 0.3, top = 1)

Answer 2

cowplot

包可以通过多种方式组装

ggplot

。

ggplot::annotate()

可用于在绘图顶部绘制箭头。

下面的示例首先绘制

map1

。在其顶部和左上角 在拐角处，我们添加一个空矩形，即

map2

的“画布”。最后， 我们用

annotate()

添加箭头。您可能想要调整 元素的坐标和大小。

这可能有助于修复剧情 将尺寸调整为正方形，以使元素的位置保持一致。 您可以通过使用具有相同高度值的

ggsave()

来做到这一点 宽度。

library(cowplot)

ggdraw(clip = "on") +
  draw_plot(map1 + theme_void()) +
  draw_grob(
    grid::rectGrob(),
    x = 0.08,
    y = .8,
    width = .2,
    height = .2
  ) +
  draw_plot(
    map2 + theme_void(),
    x = 0.08,
    y = .8,
    width = .2,
    height = .2
  ) +
  annotate(
    "segment",
    x = 0.28,
    xend = .55,
    y = 0.8,
    yend = 0.2,
    colour = "orange",
    linewidth = 2,
    arrow = arrow()
  )

Answer 3

这是一个套餐

grid

选项：

library(grid)

zoomed = viewport(
  x = .2,
  y = .8,
  width = .4,
  height = .4
)
regular = viewport(
  x = .5,
  y = .5,
  width = 1.0,
  height =1.0
)


grid.newpage()

print(map2, vp = regular)
print(map1, vp = zoomed)

grid.lines(x=c(0.8, 0.2),
              y=c(0.2,0.8),
              #id=rep(1:5, 4),
              gp=gpar(col=1:5, lwd=3),
           arrow = grid::arrow()
)