R/gisco_get_coastallines.R

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

#' Get GISCO coastlines [`sf`][sf::st_sf] polygons
#'
#' Downloads worldwide coastlines
#'
#' @family political
#'
#' @param year Release year. One of `r gsc_helper_year_docs("coastallines")`.
#'
#' @inheritParams gisco_get_countries
#'
#' @inheritSection gisco_get_countries About caching
#'
#' @source <https://gisco-services.ec.europa.eu/distribution/v2/>
#'
#' @return A [`sf`][sf::st_sf] `POLYGON` object.
#'
#' @note
#' Please check the download and usage provisions on [gisco_attributions()].
#'
#' @seealso [gisco_coastallines]
#'
#' @examplesIf gisco_check_access()
#' coast <- gisco_get_coastallines()
#'
#' library(ggplot2)
#'
#' ggplot(coast) +
#'   geom_sf(color = "#1278AB", fill = "#FDFBEA") +
#'   # Zoom on Caribe
#'   coord_sf(
#'     xlim = c(-99, -49),
#'     ylim = c(4, 30)
#'   ) +
#'   theme_minimal() +
#'   theme(
#'     panel.background = element_rect(fill = "#C7E7FB", color = NA),
#'     panel.border = element_rect(colour = "black", fill = NA)
#'   )
#' @export
gisco_get_coastallines <- function(year = "2016", epsg = "4326", cache = TRUE,
                                   update_cache = FALSE, cache_dir = NULL,
                                   verbose = FALSE, resolution = "20") {
  ext <- "geojson"

  api_entry <- gsc_api_url(
    id_giscoR = "coastallines", year = year,
    epsg = epsg, resolution = resolution, spatialtype = NULL, ext = ext,
    nuts_level = NULL, level = NULL, verbose = verbose
  )

  filename <- basename(api_entry)

  # Check if data is already available
  checkdata <- grep("COAS_RG_20M_2016_4326", api_entry)
  if (isFALSE(update_cache) && length(checkdata)) {
    dwnload <- FALSE
    data_sf <- giscoR::gisco_coastallines

    gsc_message(
      verbose,
      "Loaded from gisco_coastallines dataset. Use update_cache = TRUE",
      "to load the shapefile from the .geojson file"
    )
  } else {
    dwnload <- TRUE
  }
  if (dwnload) {
    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)
  }
  return(data_sf)
}