rasterise_landuse: Rasterise residential land use polygons

In ecological-cities/home2park: Spatial Provision of Urban Parks

Rasterise residential land use polygons

Description

Rasterise land use zones (sf_landuse) with reference to population data (sf_pop), if supplied. Multiple (a list of) output rasters will be generated if land use data for multiple years are present. If the land use data includes unnecessary land use classes, the argument subset and landuse allows the user to first subset the data to polygons defined as 'residential' land use.

Usage

rasterise_landuse(
  sf_landuse,
  subset = NULL,
  land_use = NULL,
  year = "year",
  sf_pop = NULL,
  match_landuse_pop = "recent",
  dir_rastertemplate = NULL,
  dir_processing = tempdir(),
  dir_export = tempdir(),
  overwrite = TRUE,
  wopt = list(gdal = c("COMPRESS=LZW")),
  ...
)

Arguments

sf_landuse	sf polygons of the land use zones. Data should be in a projected coordinate reference system.
subset	Named vector containing the residential land use classes of interest to retain in column land_use. Each element is named according to the integer that will be used to represent this class in the output raster. Defaults to NULL (integers will be alphabetically assigned to land use classes).
land_use	character. Specify column name of the land use classes.
year	character. Specify column name for the year within sf_landuse and sf_pop (if provided). Defaults to 'year'. Column data should be numeric.
sf_pop	(optional) sf polygons containing the population census data with column containing the census year. If absent, the output (land use rasters) will not be associated with specific population census year(s).
match_landuse_pop	character. Type of matching between sf_landuse and sf_pop, passed on to match argument in function matchyear(). Either 'exact', 'closest', 'recent' or 'soonest'. Defaults to 'recent', i.e. assumes that land use is pre-planned (and followed by population changes), rather than a result of post-monitoring (e.g. remotely-sensed).
dir_rastertemplate	character. Filepath to the raster used to define the pixel resolution, extent, nrow, ncol of the output raster; object is passed to the 'y' argument in terra::rasterize(). Defaults to the template raster generated by the function rasterise_pop() within dir_processing (see next argument).
dir_processing	character. Directory to get intermediate files generated in previous steps (e.g. rasterised population data). Defaults to tempdir().
dir_export	character. File path to directory to export output raster(s) to. Defaults to tempdir(). Set to NULL if you do not wish to export output for subsequent processing.
overwrite	logical. Argument passed to terra::writeRaster(). Defaults to TRUE.
wopt	list. Argument passed to terra::writeRaster().
...	Other arguments passed to terra::writeRaster().

Details

If population data (sf_pop) is supplied, its raster(s) must have been previously generated in the tempdir() using the function rasterise_pop(). Each year in the population data is matched to a specific year in the land use data (using the helper function matchyear()). Land use raster(s) will then be associated with a specific population census year, and removed if there are no matching population census years. Rasterised land use zones will be masked away (i.e., convert pixels to NA) at areas with no (zero) population data (for the respective matching year).

Value

List of raster files. Zero values are converted to NA. Each raster is also an intermediate file exported to the directory as defined by dir_export (defaults to tempdir()) for further processing.

Examples

## Not run: 
data(pop_sgp)
data(landuse_sgp)


# transform to projected crs
pop_sgp <- sf::st_transform(pop_sgp, sf::st_crs(32648))
landuse_sgp <- sf::st_transform(landuse_sgp, sf::st_crs(32648))


# run function
landuse_rasters <- rasterise_landuse(landuse_sgp,
                                     land_use = 'lu_desc',
                                     subset = c('1' = 'RESIDENTIAL',
                                                '2' = 'COMMERCIAL & RESIDENTIAL',
                                                '3' = 'RESIDENTIAL WITH COMMERCIAL AT 1ST STOREY',
                                                '4' = 'RESIDENTIAL / INSTITUTION'),
                                     year = 'year',
                                     sf_pop = pop_sgp,
                                     match_landuse_pop = 'recent')

## End(Not run)

ecological-cities/home2park documentation built on Dec. 6, 2023, 1:05 a.m.