R/h3_algorithms2.R

In crazycapivara/h3forr: An R Interface to H3

#' Get the parent of a given hexagon at a particular resolution
#'
#' @param h3_index character vector representing H3 indexes
#' @param res resolution; if \code{NULL}, the resolution will be set to
#' \code{h3_get_resolution(h3_index[1]) - 1}
#'
#' @return character vector of H3 indexes
#'
#' @example inst/examples/api-reference/h3-to-parent.R
#'
#' @export
h3_to_parent <- function(h3_index, res = NULL) {
  if (is.null(res)) res <- h3_get_resolution(h3_index[1]) - 1

  h3js_map("h3ToParent", h3_index, res)
}

#' Get the children/descendents of a given hexagon at a particular resolution
#'
#' @inheritParams h3_to_parent
#' @param res resolution; if \code{NULL}, the resolution will be set to
#' \code{h3_get_resolution(h3_index[1]) + 1}
#'
#' @return character vector of H3 indexes; list of charactor vectors
#' if multiple indexes are supplied
#'
#' @example inst/examples/api-reference/h3-to-children.R
#'
#' @export
h3_to_children <- function(h3_index, res = NULL) {
  if (is.null(res)) res <- h3_get_resolution(h3_index[1]) + 1

  result <- h3js_map("h3ToChildren", h3_index, res)
  if (is.array(result)) result %<>% purrr::array_tree(1)

  result
}