polygon_to_raster: Create and save raster images for different dates and times

In quadkeyr: Generate Raster Images from QuadKey-Identified Datasets

Create and save raster images for different dates and times

Description

Creates one raster by each date and time reported and saves it as a .tif.

Usage

polygon_to_raster(
  data,
  nx,
  ny,
  template,
  var = "percent_change",
  filename,
  path
)

Arguments

data	A sf POLYGON data.frame with the variable we want to represent in the raster.
nx	Integer; number of cells in x direction.
ny	Integer; number of cells in y direction.
template	A sf POLYGON data.frame
var	The column name of the variable to plot.
filename	Select a name for the file. The date and time will be included automatically in the name.
path	Path where the files should be stored.

Value

as many .tif files as dates and times in the dataset

See Also

st_as_stars, st_rasterize

missing_combinations

Examples

files <- read_fb_mobility_files(
  path_to_csvs = paste0(system.file("extdata",
    package = "quadkeyr"
  ), "/"),
  colnames = c(
    "lat", "lon",
    "quadkey", "date_time",
    "n_crisis", "percent_change"
  ),
  coltypes = list(
    lat = "d",
    lon = "d",
    quadkey = "c",
    date_time = "T",
    n_crisis = "c",
    percent_change = "c"
  )
)

# Get a regular grid and create the polygons
regular_grid <- get_regular_polygon_grid(data = files)

# Keep only the QuadKeys reported
files_polygons <- files |>
  dplyr::inner_join(regular_grid$data,
    by = c("quadkey")
  )

# Generate the raster files
polygon_to_raster(
  data = files_polygons,
  nx = regular_grid$num_cols,
  ny = regular_grid$num_rows,
  template = files_polygons,
  var = "percent_change",
  filename = "cityA",
  path = paste0(
    system.file("extdata",
      package = "quadkeyr"
    ),
    "/"
  )
)

quadkeyr documentation built on April 3, 2025, 8:52 p.m.