download_pop_rasters: Download population rasters for given country codes.
Description
This function attempts to download population rasters from WorldPop for the
specified country codes. If `dest_dir` is not provided, file paths will be
generated based on the given country codes and saved into the current
project directory (using `here::here()`). It first checks if a local file
already exists, and if so, it will skip downloading.
Invisibly returns a vector of downloaded file paths
(or NA if not found).
Arguments
country_codes
A character vector of ISO3 country codes.
dest_dir
A character vector of file paths for saving rasters.
If NULL, defaults to "<cc>_ppp_2020_constrained2.tif" in the project dir.
quiet
Logical; if TRUE, suppress status messages.
Details
The function tries a baseline URL (BSGM) for each country code. If the file
is not found there, it then tries a secondary URL (maxar_v1). If neither
location provides the file, it returns NA and prompts you to check the
WorldPop website directly.