R/weather.R

In jrnold/groundcontrol: Create a Custom Dataset of On-time Flights

# From https://mesonet.agron.iastate.edu/request/download.phtml?network=NY_ASOS
get_asos <- function(station, year, csv_output = NULL, cache = tempfile()) {
  url <- "http://mesonet.agron.iastate.edu/cgi-bin/request/asos.py?"
  dst <- file.path(cache, paste0(station, ".csv"))
  if (!file.exists(dst)) {
    query <- list(
      station = station, data = "all",
      year1 = as.character(year), month1 = "1", day1 = "1",
      year2 = as.character(year), month2 = "12", day2 = "31", tz = "GMT",
      format = "comma", latlon = "no", direct = "yes")

    dir.create(cache, showWarnings = FALSE, recursive = TRUE)
    r <- GET(url, query = query, write_disk(dst))
    stop_for_status(r)
    message("Saved file ", dst)
  }
}

download_weather <- function(data_dir, raw_dir, year, stations) {
  cache <- raw_dir
  dst <- file.path(cache, "weather")
  dir.create(dst, recursive = TRUE, showWarnings = FALSE)
  lapply(stations, get_asos, year = year, cache = dst)
  paths <- dir(dst, full.names = TRUE, pattern = ".*\\.csv")
  col_types <- cols(
    .default = col_double(),
    station = col_character(),
    valid = col_datetime(format = ""),
    skyc1 = col_character(),
    skyc2 = col_character(),
    skyc3 = col_character(),
    skyc4 = col_character(),
    presentwx = col_character(),
    metar = col_character()
  )
  all <- lapply(paths, read_csv, comment = "#", na = "M",
                col_names = TRUE, col_types = col_types)
  raw <- bind_rows(all)
  names(raw) <- c("station", "valid", "tmpf", "dwpf", "relh", "drct", "sknt",
                   "p01i", "alti", "mslp", "vsby", "gust",
                   "skyc1", "skyc2", "skyc3", "skyc4",
                   "skyl1", "skyl2", "skyl3", "skyl4", "presentwx", "metar")
  weather <-
    raw %>%
    rename_(time = ~valid) %>%
    select_(
      ~station, ~time, temp = ~tmpf, dewp = ~dwpf, humid = ~relh,
      wind_dir = ~drct, wind_speed = ~sknt, wind_gust = ~gust,
      precip = ~p01i, pressure = ~mslp, visib = ~vsby
    ) %>%
    mutate_(
      time = ~as.POSIXct(strptime(time, "%Y-%m-%d %H:%M")),
      wind_speed = ~as.numeric(wind_speed) * 1.15078, # convert to mpg
      wind_gust = ~as.numeric(wind_speed) * 1.15078,
      year = ~year,
      month = ~lubridate::month(time),
      day = ~lubridate::mday(time),
      hour = ~lubridate::hour(time)) %>%
    group_by_(~station, ~month, ~day, ~hour) %>%
    filter_(~ row_number() == 1) %>%
    select_(~station, ~year:hour, ~temp:visib) %>%
    ungroup() %>%
    filter_(~!is.na(month)) %>%
    mutate_(
      time_hour = ~ISOdatetime(year, month, day, hour, 0, 0)
    )

  save_csv(weather, file.path(raw_dir, "weather.csv"))
  save_rda(weather, file = file.path(data_dir, "weather.rda"),
           compress = "bzip2")

}