并排绘制两个县，同时保持比例

Question

有没有办法并排绘制两个县（不改变实际比例）来比较它们的大小。

我希望并排绘制圣地亚哥和圣克拉拉，以展示它们的实际大小。

谢谢

library(tigris)
library(ggplot2)

san_diego <- county_subdivisions(state = "CA", county = "San Diego County", cb = TRUE, year = NULL)

santa_clara <- county_subdivisions(state = "CA", county = "Santa Clara County", cb = TRUE, year = NULL)


gg_san_diego <- ggplot() + 
  geom_sf(data = san_diego, 
          color="black",
          fill="white", 
          size=0.25)

gg_santa_clara <- ggplot() + 
  geom_sf(data = santa_clara, 
          color="black",
          fill="white", 
          size=0.25)


gg_san_diego

gg_santa_clara

Answer 1

一种简单的方法是通过减去县的质心，然后按县名称进行分面，将县移动到同一位置。这是一个完全可重现的示例：

library(tigris)
library(tidyverse)
library(sf)

county_subdivisions(state = "CA", cb = TRUE, year = NULL,
                    county = c("San Diego County", "Santa Clara County")) %>%
  group_by(NAMELSADCO) %>%
  mutate(geometry = geometry - st_centroid(st_union(geometry))) %>%
  ggplot() + 
  geom_sf(color = "black", fill = "white") +
  facet_wrap(.~NAMELSADCO) +
  theme_void(base_size = 20) +
  theme(strip.text = element_text(margin = margin(20, 20, 20, 20)),
        panel.background = element_rect(fill = "gray95", color = NA))