Get canonical form of Z7 index

Decodes and re-encodes a Z7 index until it reaches a stable form. Every valid index is already canonical and comes back unchanged. A string whose first nonzero digit is the direction its pentagon base cell lacks names no cell; it decodes, as in DGGRID, to the lattice point its digits reach, and this function returns the index of the cell there.

Usage

hexify_z7_canonical(index, max_iterations = 128L)

Arguments

index

Character vector of Z7 index strings.

max_iterations

Maximum number of decode/encode iterations; the default is 128.

Value

A character vector of stable indices.

See also

Other hierarchical index: hexify_cell_to_index(), hexify_compare_indices(), hexify_default_index_type(), hexify_get_children(), hexify_get_parent(), hexify_get_resolution(), hexify_index_to_cell(), hexify_index_to_lonlat(), hexify_is_valid_index_type(), hexify_lonlat_to_index()

Examples

# Valid Z7 indices are stable
hexify_z7_canonical("110001")

cell <- hexify_index_to_cell("110001", aperture = 7)
identical(
  hexify_cell_to_index(cell$face, cell$i, cell$j,
    cell$resolution, aperture = 7
  ),
  "110001"
)