R/gisco_get_urban_audit.R

In dieghernan/giscoR: Download Map Data from GISCO API - Eurostat

#' Get GISCO greater cities and metropolitan areas [`sf`][sf::st_sf] objects
#'
#' @description
#' Returns polygons and points corresponding to cities, greater cities and
#' metropolitan areas included on the
#' [Urban Audit report](https://ec.europa.eu/eurostat/web/regions-and-cities)
#' of Eurostat.
#'
#' @family political
#'
#' @return A [`sf`][sf::st_sf] object specified by `spatialtype`.
#'
#' @param year Release year of the file. One
#'   of `r gsc_helper_year_docs("urban_audit")`.
#'
#' @param spatialtype Type of geometry to be returned:
#'  * `"LB"`: Labels - `POINT` object.
#'  * `"RG"`: Regions - `MULTIPOLYGON/POLYGON` object.
#'
#' @param level Level of Urban Audit. Possible values are `"CITIES"`, `"FUA"`,
#' `"GREATER_CITIES"` or `NULL`, that would download the full dataset.
#'
#' @inheritParams gisco_get_countries
#'
#' @inheritSection gisco_get_countries About caching
#'
#' @source <https://gisco-services.ec.europa.eu/distribution/v2/>
#'
#' @seealso [gisco_get_communes()], [gisco_get_lau()]
#'
#' @export
#'
#' @note
#' Please check the download and usage provisions on [gisco_attributions()].
#'
#' @examplesIf gisco_check_access()
#' \donttest{
#' cities <- gisco_get_urban_audit(year = "2020", level = "CITIES")
#'
#' if (!is.null(cities)) {
#'   bcn <- cities[cities$URAU_NAME == "Barcelona", ]
#'
#'   library(ggplot2)
#'   ggplot(bcn) +
#'     geom_sf()
#' }
#' }
gisco_get_urban_audit <- function(year = "2021", epsg = "4326",
                                  cache = TRUE, update_cache = FALSE,
                                  cache_dir = NULL, verbose = FALSE,
                                  spatialtype = "RG", country = NULL,
                                  level = NULL) {
  ext <- "geojson"

  api_entry <- gsc_api_url(
    id_giscoR = "urban_audit", year = year,
    epsg = epsg, resolution = 0,
    # Not necessary
    spatialtype = spatialtype, ext = ext, nuts_level = NULL,
    level = level, verbose = verbose
  )

  filename <- basename(api_entry)

  if (cache) {
    # Guess source to load
    namefileload <- gsc_api_cache(
      api_entry, filename, cache_dir,
      update_cache, verbose
    )
  } else {
    namefileload <- api_entry
  }

  if (is.null(namefileload)) {
    return(NULL)
  }

  # Load - geojson only so far
  data_sf <- gsc_api_load(namefileload, epsg, ext, cache, verbose)


  if (!is.null(country) && "CNTR_CODE" %in% names(data_sf)) {
    # Convert ISO3 to EUROSTAT thanks to Vincent Arel-Bundock (countrycode)
    country <- gsc_helper_countrynames(country, "eurostat")
    data_sf <- data_sf[data_sf$CNTR_CODE %in% country, ]
  }
  return(data_sf)
}