DoU_get_optimal_builtup {flexurba} | R Documentation |
Get the optimal built-up area threshold
Description
In Data Package 2023, the Degree of Urbanisation includes a "Reduce Fragmentation Option" to account for the presence of office parks, shopping malls, factories and transport infrastructure. When the setting is enabled, urban centres are created using both cells with a population density of at least 1500 inhabitants per km² and cells that have an "optimal" built-up area on permanent land. This function can be used to determine this "optimal" threshold value.
The optimal threshold is dynamically identified as the global average built-up area proportion in clusters with a density of at least 1500 inhabitants per permanent land with a minimum population of 5000 people. We empirically discovered that the Degree of Urbanisation uses the rounded up (ceiled) optimal threshold to two decimal places.
For more information: see GHSL Data Package 2023, footnote 30. The arguments of the function allow to adapt the standard specifications in order to determine an alternative "optimal" threshold.
Usage
DoU_get_optimal_builtup(
data,
density_threshold = 1500,
size_threshold = 5000,
directions = 4
)
Arguments
data |
path to the directory with the data, or named list with the data as returned by function |
density_threshold |
numeric. Minimum population density per permanent land |
size_threshold |
numeric. Minimum population size |
directions |
integer. Which cells are considered adjacent: |
Value
optimal built-up area threshold
Examples
data_belgium <- DoU_load_grid_data_belgium()
# determine the optimal built-up threshold with standard specifications
DoU_get_optimal_builtup(data_belgium)
# determine the optimal built-up threshold with custom specification
DoU_get_optimal_builtup(data_belgium,
density_threshold = 1000,
size_threshold = 3500,
directions = 8
)