So the GADM maps and data site has changed the format that is shares so new R packages have been created. As such some of the code delivered in the Feb 2025 version of the R for Biochemists 101 course delivered by the Biochemical Society doesn't work.
As of 5 March 2025, one of the file formats available is Geopackage which can be opened by the R package sf. This is the CRAN package page for the sf package and here is the Github page.
I've written some code to plot the UK.
## START
# script to plot United Kingdom as per the exercise in R101, Module 5
# install.packages("sf")
library(sf)
library(ggplot2)
# identify the URL
link <- "https://geodata.ucdavis.edu/gadm/gadm4.1/gpkg/gadm41_GBR.gpkg"
# download the data
download.file(url=link, destfile="file.gpkg", mode="wb")
# it's a big file and takes a while to download
# check layers within the data
st_layers("file.gpkg")
# this function is from the package sf
# output
# Driver: GPKG
# Available layers:
# layer_name geometry_type features fields crs_name
# 1 ADM_ADM_0 Multi Polygon 1 2 WGS 84
# 2 ADM_ADM_1 Multi Polygon 5 11 WGS 84
# 3 ADM_ADM_2 Multi Polygon 183 13 WGS 84
# 4 ADM_ADM_3 Multi Polygon 406 16 WGS 84
# 5 ADM_ADM_4 Multi Polygon 9111 14 WGS 84
# this file contains a lot of data
# open one of the layers in the file
gb <- st_read("file.gpkg", layer = "ADM_ADM_2")
# plot the map
ggplot() + geom_sf(data = gb)
# this take a while but it does work...
# pull out the data of layer 1 with 5 features
gb_1 <- st_read("file.gpkg", layer = "ADM_ADM_1")
# plot the file
ggplot() + geom_sf(data = gb_1)
# still quite slow... gives a nice map with England, Northern Ireland,
# Scotland and Wales
## END
