采样点.R

library(sf) 
library(ggspatial)
china_map <- read_sf("中华人民共和国.json")
# 添加采样点
sites <- data.frame(lon = c(116.4, 121.5, 100), lat = c(39.9, 31.2, 36))
sites_sf <- st_as_sf(sites, coords = c("lon", "lat"), crs = 4326)

ggplot() +
  geom_sf(data = china_map, color = "black", fill = NA) +
  geom_sf(data = sites_sf, color = "red", size = 3) +
  annotation_scale(location = "bl") +  # 添加比例尺
  coord_sf(crs = "+proj=laea +lat_0=40 +lon_0=104")  # 调整投影

https://datav.aliyun.com/portal/school/atlas/area_selector#&lat=30.332329214580188&lng=106.72278672066881&zoom=3.5