使用 R 语言计算各个省市区县的经纬度范围

最近有个小伙伴问了这样一个问题，他需要各个省市区县的经纬度范围，不知道如何获取，今天我们就一起来使用 R 语言计算下。

首先我们加载所需的 R 包：

library(tidyverse)
library(sf)
library(ggspatial)

下面我们会需要使用 ggplot2 绘制一副地图，设置下绘图主题，tidy_grey.R 是课程使用 R 语言绘制中国夜间灯光地图 里面的文件：

source("tidy_grey.R")

读取一份陆地国界线和九段线数据（用于等下绘图）：

read_sf("九段线.geojson") -> jdx

计算各个省份的经纬度范围

prov %>%
  mutate(id = row.names(.)) %>%
  nest(-id) %>%
  mutate(stbbox = map(data, .f = function(x){
    st_bbox(x) %>%
      as.numeric()
  })) %>%
  unnest(data) %>%
  select(-id, - geometry) %>%
  unnest(stbbox) %>%
  mutate(kind = rep(c("最小经度", "最小纬度", "最大经度", "最大纬度"), 34)) %>%
  spread(kind, stbbox) %>%
  writexl::write_xlsx("2020年每个省份的经纬度范围.xlsx")

绘图展示：

prov %>%
  mutate(id = row.names(.)) %>%
  nest(-id) %>%
  mutate(stbbox = map(data, .f = function(x){
    st_bbox(x) %>%
      st_as_sfc() %>%
      st_cast("MULTILINESTRING")
  })) %>%
  unnest(data) %>%
  select(-id, -geometry) %>%
  rename(geometry = stbbox) %>%
  mutate(geometry = map(geometry, .f = function(x){
    x[[1]]
  })) %>%
  st_sf(crs = 4326) -> provbbox

ggplot(st_simplify(prov, dTolerance = 0.02)) +
  geom_sf(fill = NA, color = "black",
          size = 0.2) +
  geom_sf(data = jdx, color = "black",
          size = 0.5) +
  geom_sf(data = provbbox, color = "#18BC9C") +
  coord_sf(crs = "+proj=lcc +lat_1=30 +lat_2=62 +lat_0=0 +lon_0=105 +x_0=0 +y_0=0 +ellps=krass +units=m +no_defs") +
  annotate("text", x = -3450000, y = 2800000,
           label = str_wrap(paste0("这幅图展示了 2020 年中国省、自治区、直辖市的经纬度范围。"), width = 25),
           family = "Songti", hjust = 0,
           color = "#580000", size = 4) +
  annotation_scale(
    width_hint = 0.2,
    text_family = "Songti",
    pad_x = unit(0.5, "cm")
  ) +
  annotation_north_arrow(
    location = "bl",
    which_north = "false",
    pad_x = unit(0.85, "cm"),
    pad_y = unit(0.5, "cm"),
    width = unit(1.6, "cm"),
    height = unit(2, "cm"),
    style = north_arrow_fancy_orienteering(
      text_family = "Songti"
    )
  ) +
  labs(caption = "绘制：微信公众号 RStata")

ggsave("2020各省份经纬度范围.png", width = 6.5, height = 6.5)

2020 年各省份经纬度范围

计算各个城市和区县的经纬度范围

方法一模一样：

# 每个城市的经纬度范围
read_sf("2020行政区划/市.shp") -> city

city %>%
  mutate(id = row.names(.)) %>%
  nest(-id) %>%
  mutate(stbbox = map(data, .f = function(x){
    st_bbox(x) %>%
      as.numeric()
  })) %>%
  unnest(data) %>%
  select(-id, - geometry) %>%
  unnest(stbbox) %>%
  mutate(kind = rep(c("最小经度", "最小纬度", "最大经度", "最大纬度"), 370)) %>%
  spread(kind, stbbox) %>%
  writexl::write_xlsx("2020年每个城市的经纬度范围.xlsx")

# 每个区县的经纬度范围
read_sf("2020行政区划/县.shp") -> county

county %>%
  mutate(id = row.names(.)) %>%
  nest(-id) %>%
  mutate(stbbox = map(data, .f = function(x){
    st_bbox(x) %>%
      as.numeric()
  })) %>%
  unnest(data) %>%
  select(-id, - geometry) %>%
  unnest(stbbox) %>%
  mutate(kind = rep(c("最小经度", "最小纬度", "最大经度", "最大纬度"), 2878)) %>%
  spread(kind, stbbox) %>%
  writexl::write_xlsx("2020年每个区县的经纬度范围.xlsx")

这样我们就得到了每个省份、城市和区县的经纬度范围：

1. 2020年每个城市的经纬度范围.xlsx
2. 2020年每个区县的经纬度范围.xlsx
3. 2020年每个省份的经纬度范围.xlsx

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