Finding the region (district, state, etc.) of a given coordinate in GADM data (in R)-CodePudding

We are using the GADM data for France, and I'm curious if we can find the region of a point based on its latitude and longitude.

So I can plot a map of France using

library(raster)
fr = getData("GADM", country="FRA", level=1)
plot(fr)

The coordinates of a point in Paris is

latitude = 48.86122650866868
longitude = 2.341541835915652

Now when I look up different regions at level 1, I get

> fr$NAME_1
 [1] "Auvergne-Rhône-Alpes"       "Bourgogne-Franche-Comté"    "Bretagne"                   "Centre-Val de Loire"       
 [5] "Corse"                      "Grand Est"                  "Hauts-de-France"            "Île-de-France"             
 [9] "Normandie"                  "Nouvelle-Aquitaine"         "Occitanie"                  "Pays de la Loire"          
[13] "Provence-Alpes-Côte d'Azur"

Is it possible to extract the region of that coordinate, which should be Île-de-France?

CodePudding user response：

with package {sf}:

library(sf)

my_point <- st_point(c(2.3415, 48.86122))

## convert fr to class sf
fr <- st_as_sf(fr)

i <- st_within(my_point, fr)

fr[as.integer(i),]$NAME_1

output:

[1] "Île-de-France"

edit to check, map point and provinces with labels:


library(ggplot2)

## set coordinate reference system for my_point
## to EPSG 4326 (WGS84):
my_point <- st_sfc(my_point, crs = 4326)

fr %>%
ggplot(mapping = aes(geometry = geometry))  
  geom_sf()  
  geom_sf_label(aes(label = NAME_1))  
  geom_sf(my_point, mapping = aes(geometry = geometry))