The i-th child of each cell

Returns one descendant of each cell at a finer resolution without enumerating the others: the i-th element of what a5_cell_to_children() would return. Useful for random draws from large cells, where building the full child list to pick one element is wasteful.

Usage

a5_cell_child(cell, resolution, i)

Arguments

cell

An a5_cell vector.

resolution

Integer scalar target resolution, at or finer than every cell's own resolution.

i

Integer vector of 1-based child positions, recycled against cell. Must lie within 1:a5_get_num_children(res, resolution) for each cell's resolution res; out of range is an error.

Value

An a5_cell vector the same length as cell. NA where cell or i is NA.

See also

a5_cell_to_children(), a5_get_num_children()

Examples

cell <- a5_lonlat_to_cell(-3.19, 55.95, resolution = 5)
a5_cell_child(cell, resolution = 7, i = 1:16)
#> <a5_cell[16]>
#>  [1] 6314200000000000 6314600000000000 6314a00000000000 6314e00000000000
#>  [5] 6315200000000000 6315600000000000 6315a00000000000 6315e00000000000
#>  [9] 6316200000000000 6316600000000000 6316a00000000000 6316e00000000000
#> [13] 6317200000000000 6317600000000000 6317a00000000000 6317e00000000000
identical(a5_cell_child(cell, 7, 1:16), a5_cell_to_children(cell, 7))
#> [1] TRUE