Make a grid over a simple feature bounding box

Create a grid with an id column and optionally a set number of columns and rows. This documentation is incomplete the function may change.

Usage

st_make_grid_ext(
  x,
  ...,
  unit = NULL,
  crs = NULL,
  ncol = NULL,
  nrow = NULL,
  n = NULL,
  gutter = 0,
  desc = FALSE,
  cellsize = NULL,
  what = NULL,
  style = "rect",
  .id = "id",
  filter = FALSE,
  trim = FALSE
)

Arguments

x

A sf, sfc, or bbox object, Default: NULL. Required.

...

Arguments passed on to st_bbox_ext

nudge: Passed as to parameter st_nudge() when not NULL. A numeric vector, a sf object, or any other object that can be converted to a simple feature collection with as_sfc()..
dist: buffer distance in units. Optional.
diag_ratio: ratio of diagonal distance of area's bounding box used as buffer distance. e.g. if the diagonal distance is 3000 meters and the "diag_ratio = 0.1" a 300 meter will be used. Ignored when dist is provided.
allow_list: If TRUE, allow sf list objects as an input and use purrr::map() to apply the provided parameters to each object within the list to return as a new sf list object.
asp: Aspect ratio of width to height as a numeric value (e.g. 0.33) or character (e.g. "1:3"). If numeric, get_asp() returns the same value without modification.

unit

Units for buffer. Supported options include "meter", "foot", "kilometer", and "mile", "nautical mile" Common abbreviations (e.g. "km" instead of "kilometer") are also supported. Distance in units is converted to units matching GDAL units for x; defaults to "meter"

crs

Coordinate reference system of bounding box to return; defaults to NULL which maintains the crs of the input object.

ncol, nrow

Used to set n if either are not NULL; defaults to NULL. row and id are added as columns to the grid if they are provided.

n

If n is NULL and square is TRUE, the grid is set automatically to be 10 cells wide, Default: NULL

gutter

Distance in units between each column cell; gutter effectively serves as a margin as the negative buffer is applied to all cells (including those at the edges of the grid).

desc

If TRUE, reverse standard order of cell id numbering; defaults FALSE

cellsize

numeric of length 1 or 2 with target cellsize: for square or rectangular cells the width and height, for hexagonal cells the distance between opposite edges (edge length is cellsize/sqrt(3)). A length units object can be passed, or an area unit object with area size of the square or hexagonal cell.

what

"polygons", "corners", "centers"; set to centers automatically if style is "circle", "circle_offset" but a buffer is applied to return circular polygons.

style

Style of cell to return with options including "rect", "square", "hex", "flat_top_hex", "circle", "circle_offset"

.id

A name to use for the cell id column. Defaults to "id".

filter

If TRUE (or if trim is TRUE) filter grid geometry by x using st_filter_ext

trim

If TRUE, x is trimmed to y with st_trim().

Examples

nc <- sf::read_sf(system.file("shape/nc.shp", package = "sf"))

# Make a 2 by 2 grid across a location with a 1000 meter gutter between each cell
plot(
  st_make_grid_ext(
    x = nc[24, ],
    dist = 500,
    unit = "meter",
    ncol = 2,
    nrow = 2,
    gutter = 1000
  )
)


# Make a 5 by 5 grid with a 8.5 by 11 aspect ratio filtered to x
plot(
  st_make_grid_ext(
    x = nc[24, ],
    asp = 8.5 / 11,
    ncol = 5,
    nrow = 5,
    filter = TRUE
  )
)


# Make a 4 by 5 grid of circles trimmed to x boundaries
plot(
  st_make_grid_ext(
    x = nc[24, ],
    ncol = 4,
    nrow = 5,
    style = "circle_offset",
    trim = TRUE
  ),
  max.plot = 1
)

Usage

Arguments

See also

Examples