The grid cell classification of the Degree of Urbanisation requires three different inputs:
a built-up area grid
a population grid
a land grid
The function rescales the built-up area and land grid if necessary (see details) and computes the population and built-up area per permanent land by dividing the respective grids by the land layer.
DoU_preprocess_grid(
directory,
filenames = c("BUILT_S.tif", "POP.tif", "LAND.tif"),
rescale_land = TRUE,
rescale_built = TRUE
)named listed with the required data to execute the grid cell classification procedure. The list contains following elements:
built: built-up area grid
pop: population grid
land: land grid
pop_per_land: population per area of permanent land
built_per_land: built-up area per permanent land
metadata_BUILT_S: the metadata of the built-up area grid
metadata_POP: the metadata of the population grid
metadata_LAND: the metadata of the land grid.
character. Path to the directory where the three input grids are saved (for example generated by the function download_GHSLdata())
vector of length 3 with the filenames of the built-up area, population and land grid
logical. Whether to rescale the values of the land grid (see details)
logical. Whether to rescale the values of the built-up area grid (see details)
The values of the land grid and built-up area grid should range from 0 to 1, representing the proportion of permanent land and built-up area respectively. However, the grid values of the GHSL are standard in m². With a cell size of 1 km², the values thus range from 0 to 1 000 000. The two grids can be rescaled by setting rescale_land=TRUE and/or rescale_built=TRUE respectively.