Collection and pre-processing of cartographic information for Cameroon

Here we demonstrate how we have downloaded and pre-processed the cartographic information for Cameroon which is included in the package.

require(terra)
#> Loading required package: terra
#> terra 1.7.65
require(sf)
#> Loading required package: sf
#> Linking to GEOS 3.10.2, GDAL 3.4.1, PROJ 8.2.1; sf_use_s2() is TRUE
require(geodata)
#> Loading required package: geodata

if(!require(mapview, quietly = TRUE)) 
  cat("We suggest installing the pacakge mapview for interactive visualisation",
      "of cartography from within R")

Administrative borders

Download cartography from the Global Administrative Borders Database (GADM, https://gadm.org/) directly from within R.


cmr_admin3 <- geodata::gadm(
  country = "Cameroon",
  level=3,          # 3rd admin level
  resolution = 2,   # low-res
  path = tempdir()
)
# mapview(cmr_admin3, zcol = "NAME_3")


## This only works locally.
prodel_path <- "/home/facu/CmisSync/Cirad/Sites/PRODEL/documentLibrary/carto"
water_bodies <- read_sf(file.path(prodel_path, "wb_cam.shp.shp"))

national_parks <- read_sf(
  file.path(prodel_path, "WDPA_Mar2018_CMR-shapefile"),
  "WDPA_Mar2018_CMR-shapefile-polygons"
)

# Not using this for the moment
ps_cam <- terra::rast("ps_cam.tif")

animal_density_world <- terra::rast(file.path(prodel_path, "glw", "WdCt8k_vf_Mn_Rw_To.tif"))
animal_density <- terra::mask(
  crop(
    animal_density_world,
    terra::ext(cmr_admin3)
  ),
  cmr_admin3
)

# plot(animal_density)
# summary(animal_density$WdCt8k_vf_Mn_Rw_To)

Save pre-processed cartography for use within the package

Prefer standard and modern Open Geospatial Consortium (OGC) formats: GeoPackage for vector maps and GeoTiff for raster images.

cmr_dir <- "./inst/cartography/CMR"
dir.create(cmr_dir, recursive = TRUE)

writeVector(cmr_admin3, file.path(cmr_dir, "cmr_admin3.gpkg"))
write_sf(water_bodies, file.path(cmr_dir, "water_bodies.gpkg"), layer = "water_bodies", driver = "GPKG")
write_sf(national_parks, file.path(cmr_dir, "national_parks.gpkg"), layer = "national_parks", driver = "GPKG")

terra::writeRaster(animal_density, file.path(cmr_dir, "animal.density.tif"))

Facundo Muñoz

2024-03-19

Administrative borders

Save pre-processed cartography for use within the package