Collection and pre-processing of cartographic information for Cameroon

Facundo Muñoz

2019-06-12

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

require(raster)
#> Loading required package: raster
#> Loading required package: sp
require(rgdal)
#> Loading required package: rgdal
#> rgdal: version: 1.4-4, (SVN revision 833)
#>  Geospatial Data Abstraction Library extensions to R successfully loaded
#>  Loaded GDAL runtime: GDAL 2.2.2, released 2017/09/15
#>  Path to GDAL shared files: /usr/share/gdal/2.2
#>  GDAL binary built with GEOS: TRUE 
#>  Loaded PROJ.4 runtime: Rel. 4.9.2, 08 September 2015, [PJ_VERSION: 492]
#>  Path to PROJ.4 shared files: (autodetected)
#>  Linking to sp version: 1.3-1

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 <- getData('GADM', country = "CMR", level=3)
# mapview(cmr_admin3, zcol = "NAME_3")

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

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

# Not using this for the moment
ps_cam <- raster("ps_cam.tif")

animal_density_world <- raster(file.path(prodel_path, "glw", "WdCt8k_vf_Mn_Rw_To.tif"))
animal_density <- mask(crop(animal_density_world, extent(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)

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

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