MeteoCat service
In meteospain: Access to Spanish Meteorological Stations Services

# use eval = NOT_CRAN in the chunks connecting to API, to avoid errors or warnings in CRAN checks
NOT_CRAN <- identical(tolower(Sys.getenv("NOT_CRAN")), "true")
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  purl = NOT_CRAN
)

# env keyring
withr::local_options(list("keyring_backend" = "env"))

library(meteospain)
library(dplyr)
library(ggplot2)
library(ggforce)
library(units)
library(sf)
library(keyring)

MeteoCat service

MeteoCat is the Catalonian meteorologic service. It offers access to different meteorological data and information, being one of their main missions to curate and circulate data from meteorological stations. meteospain only access to the automatic meteorological stations network data.

MeteoCat options

Temporal resolution

meteospain offers access to the MeteoCat API at different temporal resolutions:

"instant", returning the latest 4 hours of measures for all or selected stations.
"hourly", returning all measures (some stations has timesteps of 30 min, others 60 min, others more) for all or selected stations.
"daily", returning daily aggregates for the month in the date provided, i.e. if '2020-04-10' is provided as start_date, all daily values for April 2020 will be returned.
"monthly", returning monthly aggregates for the year in the date provided, i.e. if '2020-04-10' is provided as start_date, all monthly values for 2020 will be returned.
"yearly", returning yearly aggregates for all years available. In this case date provided is ignored.

In "daily" and "monthly", a start_date argument must be provided, indicating the date from which retrieve the data as explained earlier. For more info see vignette('api_limits', package = 'meteospain').

Stations

meteospain access the data in the MeteoCat API collecting all stations. If a character vector of stations codes is supplied in the stations argument, a filter step is done before returning the data to maintain only the stations supplied.

MeteoCat API Key

MeteoCat API only allow access to the data with a personal API Key. This token must be included in the api_key argument of meteocat_options function.
To obtain the API Key, please visit https://apidocs.meteocat.gencat.cat/ and follow the instructions there.

It is not advisable to use the keys directly in any script shared or publicly available (github...), neither store them in plain text files. One option is using the keyring package for managing and accessing keys:

r install.packages('keyring') library(keyring) key_set('meteocat') # A prompt asking for the secret (the API Key) will appear.

Examples

# current day, all stations
api_options <- meteocat_options(
  resolution = 'instant',
  api_key = key_get('meteocat')
)
api_options

# current day, all stations
fake_api <- meteocat_options(
  resolution = 'instant',
  api_key = 'my_api_key'
)
fake_api

# daily, all stations
api_options <- meteocat_options(
  resolution = 'daily',
  start_date = as.Date('2020-04-10'),
  api_key = key_get('meteocat')
)
api_options

# daily, all stations
fake_api <- meteocat_options(
  resolution = 'daily',
  start_date = as.Date('2020-04-25'),
  api_key = 'my_api_key'
)
fake_api

MeteoCat stations info

Accessing station metadata for MeteoCat is simple:

get_stations_info_from('meteocat', api_options)

MeteoCat data

api_options <- meteocat_options(
  resolution = 'monthly',
  start_date = as.Date('2020-04-01'),
  api_key = key_get('meteocat')
)
catalunya_2020 <- get_meteo_from('meteocat', options = api_options)
catalunya_2020

Visually:

catalunya_2020 |>
  units::drop_units() |>
  mutate(month = lubridate::month(timestamp, label = TRUE)) |>
  ggplot() +
  geom_sf(aes(colour = mean_temperature)) +
  facet_wrap(vars(month), ncol = 4) +
  scale_colour_viridis_c()

catalunya_2020 |>
  mutate(month = lubridate::month(timestamp, label = TRUE)) |>
  ggplot() +
  geom_histogram(aes(x = precipitation)) +
  facet_wrap(vars(month), ncol = 4)