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

Source:`R/make_grid.R`

`st_make_grid.Rd`

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

## Arguments

- x
- 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.

- 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 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 = st_read(system.file("shape/nc.shp", package="sf"))
#> Reading layer `nc' from data source
#> `/home/runner/work/_temp/Library/sf/shape/nc.shp' using driver `ESRI Shapefile'
#> Simple feature collection with 100 features and 14 fields
#> Geometry type: MULTIPOLYGON
#> Dimension: XY
#> Bounding box: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
#> Geodetic CRS: NAD27
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)
```