Improve alert functions

NAMESPACE

@@ -1,5 +1,6 @@
 # Generated by roxygen2: do not edit by hand
 
+export(aemet_alert_zones)
 export(aemet_alerts)
 export(aemet_api_key)
 export(aemet_beaches)
@@ -55,5 +56,5 @@ importFrom(rlang,.data)
 importFrom(stats,aggregate)
 importFrom(stats,approx)
 importFrom(utils,head)
-importFrom(utils,packageVersion)
 importFrom(utils,tail)
+importFrom(utils,unzip)

NEWS.md

@@ -1,6 +1,9 @@
 # climaemet (development version)
 
--   New function: `aemet_alerts()`.
+-   New functions:
+    -   `aemet_alerts()` to get current meteorological alerts issued by AEMET.
+    -   Helper function `aemet_alert_zones()` to obtain the zoning defined by
+        AEMET for the alerts.
 -   Increase timeout limit with `httr2::req_timeout()`.
 -   Better management of non valid/duplicated/empty API keys.
 

R/aemet_alert_zones.R

@@ -0,0 +1,114 @@
+#' AEMET alert zones
+#'
+#' Get AEMET alert zones.
+#'
+#' @family aemet_api_data
+#'
+#'
+#' @inheritParams aemet_beaches
+#'
+#'
+#' @return A [`tibble`][tibble::tibble()] or a \CRANpkg{sf} object.
+#'
+#'
+#' @seealso [aemet_alerts()]
+#'
+#' @details
+#' The first result of the call on each session is (temporarily) cached in
+#' the assigned [tempdir()] for avoiding unneeded API calls.
+#'
+#' @source
+#'
+#' <https://www.aemet.es/es/eltiempo/prediccion/avisos/ayuda>. See also
+#' Annex 2 and Annex 3 docs, linked in this page.
+#'
+#'
+#' @examplesIf aemet_detect_api_key()
+#' library(tibble)
+#' alert_zones <- aemet_alert_zones()
+#' alert_zones
+#'
+#' # Cached during this R session
+#' alert_zones2 <- aemet_alert_zones(verbose = TRUE)
+#'
+#' identical(alert_zones, alert_zones2)
+#'
+#' # Select an map beaches
+#' library(dplyr)
+#' library(ggplot2)
+#'
+#'
+#' # Galicia
+#' alert_zones_sf <- aemet_alert_zones(return_sf = TRUE) %>%
+#'   filter(COD_CCAA == "71")
+#'
+#' # Coast zones are identified by a "C" in COD_Z
+#' alert_zones_sf$type <- ifelse(grepl("C$", alert_zones_sf$COD_Z),
+#'   "Coast", "Mainland"
+#' )
+#'
+#'
+#' ggplot(alert_zones_sf) +
+#'   geom_sf(aes(fill = NOM_PROV)) +
+#'   facet_wrap(~type) +
+#'   scale_fill_brewer(palette = "Blues")
+#'
+#' @export
+aemet_alert_zones <- function(verbose = FALSE, return_sf = FALSE) {
+  # Validate inputs----
+  stopifnot(is.logical(verbose))
+  stopifnot(is.logical(return_sf))
+
+  cached_sf <- file.path(tempdir(), "aemet_alert_zones.gpkg")
+  cached_date <- file.path(tempdir(), "aemet_alert_zone_date.rds")
+
+  if (file.exists(cached_sf)) {
+    sf_areas <- sf::read_sf(cached_sf)
+    dat <- readRDS(cached_date)
+
+    if (verbose) {
+      message(
+        "Loading alert zones from temporal cached file saved at ",
+        format(dat, usetz = TRUE)
+      )
+    }
+  } else {
+    # download beaches
+    url <- paste0(
+      "https://www.aemet.es/documentos/es/eltiempo/prediccion/",
+      "avisos/plan_meteoalerta/",
+      "AEMET-meteoalerta-delimitacion-zonas.zip"
+    )
+    r <- httr2::request(url)
+
+    outdir <- file.path(tempdir(), "alertzones")
+    outfile <- file.path(outdir, "alertzones.zip")
+    if (!dir.exists(outdir)) dir.create(outdir, recursive = TRUE)
+
+    r <- httr2::req_perform(r, path = outfile)
+
+    # unzip
+    unzip(outfile, exdir = outdir, junkpaths = TRUE)
+
+    # Get shp files
+    shpf <- list.files(outdir, pattern = ".shp$", full.names = TRUE)
+
+    sf_areas <- lapply(shpf, sf::read_sf)
+    sf_areas <- dplyr::bind_rows(sf_areas)
+    sf_areas <- sf::st_make_valid(sf_areas)
+    sf_areas <- sf::st_transform(sf_areas, 4326)
+
+
+    # Cache on temp dir
+    sf::st_write(sf_areas, cached_sf, quiet = TRUE)
+    saveRDS(Sys.time(), cached_date)
+  }
+
+  # Validate sf----
+  if (!return_sf) {
+    sf_areas <- sf::st_drop_geometry(sf_areas)
+    sf_areas <- dplyr::as_tibble(sf_areas)
+  }
+
+  sf_areas
+}