Returns, for each centre cell, the cells reachable within k hops,
including the centre cell itself, as an a5_covering.
Arguments
- cell
An a5_cell vector of centre cells.
- k
Non-negative integer scalar, number of hops.
- vertex
Logical scalar. If
FALSE(default), only edge-sharing neighbours are traversed. IfTRUE, vertex-sharing neighbours are included too.
Value
An a5_covering vector the same length as cell, at the
resolution of each centre cell. NA where cell is NA. Use
a5_uncompact() for the cells.
See also
a5_spherical_cap() for distance-based selection.
Examples
cell <- a5_lonlat_to_cell(-3.19, 55.95, resolution = 8)
disk <- a5_grid_disk(cell, k = 1)
disk
#> <a5_covering[1]>
#> [1] res 8: 6 cells (6 stored)
a5_uncompact(disk)
#> <a5_cell[6]>
#> [1] 6316080000000000 63bb880000000000 63bb980000000000 63bba80000000000
#> [5] 63beb80000000000 63bec80000000000
cells <- a5_lonlat_to_cell(c(-3.19, 0), c(55.95, 0), resolution = 5)
a5_grid_disk(cells, k = 2) # one covering per cell
#> <a5_covering[2]>
#> [1] res 5: 17 cells (14 stored) res 5: 17 cells (11 stored)