创建多边形的R包concaveman的替代方案

# 安装并加载必要的包
install.packages("sf")
install.packages("dplyr")
library(sf)
library(dplyr)

# 创建一个数据框
data <- data.frame(
  id = 1:3,
  lon = c(-1, 0, 1),
  lat = c(0, 1, 0)
)

# 将数据框转换为 sf 对象
points_sf <- st_as_sf(data, coords = c("lon", "lat"), crs = 4326)

# 创建多边形
polygons_df <- tibble(
  id = 1,
  part_id = 1:3,
  lon = c(-1, 0, 1, -1),
  lat = c(0, 1, 0, 0)
)

polygons_sf <- st_as_sf(polygons_df, coords = c("lon", "lat"), crs = 4326) %>%
  group_by(id) %>%
  summarise(geometry = st_union(geometry))

# 查看结果
print(polygons_sf)

# 检查坐标系
st_crs(points_sf)
st_crs(polygons_sf)

# 确保几何对象类型一致
polygons_sf <- polygons_sf %>% st_cast("POLYGON")