Read gridded HYDE population onto WHEP's grid.

Reads a HYDE baseline-scenario population count (native 5-arcmin ESRI ASCII grid, people per native cell) for one or more calendar years and, by default, aggregates it to WHEP's 0.5-degree grid by summing the 6x6 fine cells inside each 0.5-degree block, since population count is an extensive quantity. Each requested year is read from its own "{year}AD_pop.zip" archive, which holds the total (popc), urban (urbc) and rural (rurc) counts on the same grid.

Usage

read_hyde_population(
  hyde_dir = NULL,
  years = NULL,
  variable = c("total", "urban", "rural"),
  aggregate = TRUE,
  example = FALSE
)

Arguments

hyde_dir

Path to the directory holding the HYDE "{year}AD_pop.zip" archives. Defaults to Sys.getenv("WHEP_HYDE_DIR").

years

Integer vector of calendar years to read (AD, so >= 1). Required: each year is a real unzip-and-parse of a ~150MB archive, so there is no default range.

variable

Which population count to read: "total" (default, HYDE popc), "urban" (urbc) or "rural" (rurc). The output column is named after it.

aggregate

If TRUE (default), sum the fine cells to WHEP's 0.5-degree grid. If FALSE, return the native 5-arcmin cells, keyed by their own centres, for a consumer whose target grid is not 0.5 degrees.

example

If TRUE, return a small fixture instead of reading data. Defaults to FALSE.

Value

A tibble with lon, lat, year and one count column named after variable: total_pop, urban_pop or rural_pop (people in the cell that year). Cells HYDE marks as no-data are absent, never zero.

Examples

read_hyde_population(example = TRUE)
#> # A tibble: 1 × 4
#>     lon   lat  year total_pop
#>   <dbl> <dbl> <int>     <dbl>
#> 1 -0.25 -0.25  2020     12000
read_hyde_population(variable = "urban", example = TRUE)
#> # A tibble: 1 × 4
#>     lon   lat  year urban_pop
#>   <dbl> <dbl> <int>     <dbl>
#> 1 -0.25 -0.25  2020     12000