R/ha_layer.R

In healthatlas: Explore and Import 'Metopio' Health Atlas Data and Spatial Layers

#' List Geographic Layers
#' 
#' @description
#' List all geographic layers available.
#' 
#' @return Layer information tibble.
#' @export
#'
#' @examples
#' \donttest{
#' ha_set("chicagohealthatlas.org")
#' 
#' ha_layers()
#' }
ha_layers <- function() {
  body <- ha_api_layers_req() |>
    ha_req_perform()  |>
    ha_resp_body("results")

  output <- body[c("name", "slug", "description", "shapes")]
  colnames(output) <- c("layer_name", "layer_key", "layer_description", "layer_url")

  tibble::as_tibble(output)
}

#' Obtain Geographic Layer
#'
#' @description
#' Import geographic layer as a `sf` object.
#' @param layer_key Unique ID for a geographic layer.
#' @param progress Display a progress bar?
#' 
#' @return `sf` geographic layer.
#' @export
#'
#' @examples
#' \donttest{
#' ha_set("chicagohealthatlas.org")
#' 
#' ha_layer("zip", progress = FALSE)
#' }
ha_layer <- function(layer_key, progress = TRUE) {
  chk::chk_not_missing(layer_key, x_name = "`layer_key`")
  chk::chk_string(layer_key)
  chk::chk_logical(progress)

  body <- ha_api_geographies_req(layer_key) |>
    ha_req_perform_iterative(progress) |>
    ha_resp_body_iterative()

  output <- body
  names(output)[names(output) == "layer"] <- "layer_key"

  layers <- ha_layers()
  layer_url <- layers[layers$layer_key == layer_key, "layer_url"]
  layer_sf <- sf::read_sf(layer_url) |>
    subset(select = "id")
  colnames(layer_sf) <- c("geoid", "geometry")

  tibble::as_tibble(output) |>
    merge(layer_sf, by = "geoid", all.x = TRUE) |>
    sf::st_as_sf(crs = 4326)
}