chopin (version 0.9.4)

par_pad_grid: Get a set of computational grids

Description

Using input points, the bounding box is split to the predefined numbers of columns and rows. Each grid will be buffered by the radius.

Usage

par_pad_grid(
  input,
  mode = c("grid", "grid_advanced", "grid_quantile"),
  nx = 10L,
  ny = 10L,
  grid_min_features = 30L,
  padding = NULL,
  unit = NULL,
  quantiles = NULL,
  merge_max = NULL,
  return_wkt = FALSE,
  ...
)

Value

A list of two,

• original: exhaustive (filling completely) and non-overlapping grid polygons in the class of input

• padded: a square buffer of each polygon in original. Used for computation.

Arguments

input

sf or Spat* object.

mode

character(1). Mode of region construction. One of

• "grid" (simple grid regardless of the number of features in each grid)

• "grid_advanced" (merging adjacent grids with smaller number of features than grid_min_features). The argument grid_min_features should be specified.

• "grid_quantile" (x and y quantiles): an argument quantiles should be specified.

nx

integer(1). The number of grids along x-axis.

ny

integer(1). The number of grids along y-axis.

grid_min_features

integer(1). A threshold to merging adjacent grids

padding

numeric(1). A extrusion factor to make buffer to clip actual datasets. Depending on the length unit of the CRS of input.

unit

character(1). The length unit for padding (optional). units::set_units is used for padding when sf object is used. See link for the list of acceptable unit forms.

quantiles

numeric. Quantiles for grid_quantile mode.

merge_max

integer(1). Maximum number of grids to merge per merged set.

return_wkt

logical(1). Return WKT format. When TRUE, the return value will be a list of two WKT strings.

...

arguments passed to the internal function

Author

Insang Song

See Also

Other Parallelization: par_cut_coords(), par_grid(), par_grid_mirai(), par_hierarchy(), par_hierarchy_mirai(), par_make_grid(), par_merge_grid(), par_multirasters(), par_multirasters_mirai(), par_pad_balanced(), par_split_list()

Examples

lastpar <- par(mfrow = c(1, 1))
# data
library(sf)
options(sf_use_s2 = FALSE)
ncpath <- system.file("shape/nc.shp", package = "sf")
nc <- read_sf(ncpath)
nc <- st_transform(nc, "EPSG:5070")

# run: nx and ny should strictly be integers
nc_comp_region <-
  par_pad_grid(
    nc,
    mode = "grid",
    nx = 4L, ny = 2L,
    padding = 10000)
par(mfcol = c(1, 2))
plot(nc_comp_region$original$geometry)
plot(nc_comp_region$padded$geometry)

nc_comp_region_wkt <-
  par_pad_grid(
    nc,
    mode = "grid",
    nx = 4L, ny = 2L,
    padding = 10000,
    return_wkt = TRUE)
nc_comp_region_wkt$original
nc_comp_region_wkt$padded

par(lastpar)