grd_cell: Grid cell operators

In wk: Lightweight Well-Known Geometry Parsing

Grid cell operators

Description

Grid cell operators

Usage

grd_cell(grid, point, ..., snap = grd_snap_next)

grd_cell_range(
  grid,
  bbox = wk_bbox(grid),
  ...,
  step = 1L,
  snap = grd_snap_next
)

grd_cell_rct(grid, i, j = NULL, ...)

## S3 method for class 'wk_grd_rct'
grd_cell_rct(grid, i, j = NULL, ..., out_of_bounds = "keep")

## S3 method for class 'wk_grd_xy'
grd_cell_rct(grid, i, j = NULL, ..., out_of_bounds = "keep")

grd_cell_xy(grid, i, j = NULL, ...)

## S3 method for class 'wk_grd_rct'
grd_cell_xy(grid, i, j = NULL, ..., out_of_bounds = "keep")

## S3 method for class 'wk_grd_xy'
grd_cell_xy(grid, i, j = NULL, ..., out_of_bounds = "keep")

Arguments

grid	A grd_xy(), grd_rct(), or other object implementing ⁠grd_*()⁠ methods.
point	A handleable of points.
...	Unused
snap	A function that transforms real-valued indices to integer indices (e.g., floor(), ceiling(), or round()). For grd_cell_range(), a list() with exactly two elements to be called for the minimum and maximum index values, respectively.
bbox	An rct() object.
step	The difference between adjascent indices in the output
i, j	1-based index values. i indices correspond to decreasing y values; j indices correspond to increasing x values. Values outside the range 1:nrow|ncol(data) will be censored to NA including 0 and negative values.
out_of_bounds	One of 'keep', 'censor', 'discard', or 'squish'

Value

• grd_cell(): returns a list(i, j) of index values corresponding to the input points and adjusted according to snap. Index values will be outside dim(grid) for points outside wk_bbox(grid) including negative values.

• grd_cell_range() returns a slice describing the range of indices in the i and j directions.

• grd_cell_rct() returns a rct() of the cell extent at ⁠i, j⁠.

• grd_cell_xy() returns a xy() of the cell center at ⁠i, j⁠.

Examples

grid <- grd(nx = 3, ny = 2)
grd_cell(grid, xy(0.5, 0.5))
grd_cell_range(grid, grid$bbox)
grd_cell_rct(grid, 1, 1)
grd_cell_xy(grid, 1, 1)

wk documentation built on Oct. 12, 2024, 1:07 a.m.