grd_cell: Grid cell operators

In paleolimbot/grd: Raster and Grid Geometry

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 'grd_rct'
grd_cell_rct(grid, i, j = NULL, ..., out_of_bounds = "keep")

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

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

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

## S3 method for class '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 wk::rct() object.
step	The difference between adjascent indices in the output
i	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.
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 wk::rct() of the cell extent at i, j.

• grd_cell_xy() returns a wk::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)

paleolimbot/grd documentation built on Dec. 22, 2021, 6:38 a.m.