sf: st_make_grid – R documentation

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st_make_grid

Create a regular tesselation over the bounding box of an sf or sfc object

Description

Create a square or hexagonal grid covering the bounding box of the geometry of an sf or sfc object

Usage

st_make_grid(
  x,
  cellsize = c(diff(st_bbox(x)[c(1, 3)]), diff(st_bbox(x)[c(2, 4)]))/n,
  offset = st_bbox(x)[c("xmin", "ymin")],
  n = c(10, 10),
  crs = if (missing(x)) NA_crs_ else st_crs(x),
  what = "polygons",
  square = TRUE,
  flat_topped = FALSE
)

Arguments

`x`	object of class sf or sfc
`cellsize`	target cellsize
`offset`	numeric of length 2; lower left corner coordinates (x, y) of the grid
`n`	integer of length 1 or 2, number of grid cells in x and y direction (columns, rows)
`crs`	object of class `crs`; coordinate reference system of the target of the target grid in case argument `x` is missing, if `x` is not missing, its crs is inherited.
`what`	character; one of: `"polygons"`, `"corners"`, or `"centers"`
`square`	logical; if `FALSE`, create hexagonal grid
`flat_topped`	logical; if `TRUE` generate flat topped hexagons, else generate pointy topped

Value

Object of class sfc (simple feature geometry list column) with, depending on what and square, square or hexagonal polygons, corner points of these polygons, or center points of these polygons.

Examples

plot(st_make_grid(what = "centers"), axes = TRUE)
plot(st_make_grid(what = "corners"), add = TRUE, col = 'green', pch=3)
sfc = st_sfc(st_polygon(list(rbind(c(0,0), c(1,0), c(1,1), c(0,0)))))
plot(st_make_grid(sfc, cellsize = .1, square = FALSE))
plot(sfc, add = TRUE)
# non-default offset:
plot(st_make_grid(sfc, cellsize = .1, square = FALSE, offset = c(0, .05 / (sqrt(3)/2))))
plot(sfc, add = TRUE)
nc = read_sf(system.file("shape/nc.shp", package="sf"))
g = st_make_grid(nc)
plot(g)
plot(st_geometry(nc), add = TRUE)
# g[nc] selects cells that intersect with nc:
plot(g[nc], col = '#ff000088', add = TRUE)

sf

Simple Features for R

v0.9-8

GPL-2 | MIT + file LICENSE

Authors

Edzer Pebesma [aut, cre] (<https://orcid.org/0000-0001-8049-7069>), Roger Bivand [ctb] (<https://orcid.org/0000-0003-2392-6140>), Etienne Racine [ctb], Michael Sumner [ctb], Ian Cook [ctb], Tim Keitt [ctb], Robin Lovelace [ctb], Hadley Wickham [ctb], Jeroen Ooms [ctb] (<https://orcid.org/0000-0002-4035-0289>), Kirill Müller [ctb], Thomas Lin Pedersen [ctb], Dan Baston [ctb]

Initial release