R/get_saq_simple_summaries.R

In saqgetr: Import Air Quality Monitoring Data in a Fast and Easy Way

#' Function to get simple summaries of air quality observations. 
#' 
#' @param file File of simple summaries table. 
#' 
#' @param summary Summary period to import. Can either be \code{"annual_means"} or
#'  \code{"monthly_means"}. 
#' 
#' @param tz Time zone for the observations' dates. 
#' 
#' @author Stuart K. Grange.
#' 
#' @return Tibble. 
#' 
#' @examples 
#' 
#' \donttest{
#' 
#' # Import annual means
#' data_annual <- get_saq_simple_summaries(summary = "annual_means")
#' 
#' }
#' 
#' \dontrun{
#' 
#' # Import monthly means, quite a large request so will take some time
#' data_month <- get_saq_simple_summaries(summary = "monthly_means")
#' 
#' }
#' 
#' @export
get_saq_simple_summaries <- function(file = NA, summary = "annual_means", 
                                     tz = "UTC") {
  
  
  # Parse and check arguments
  summary <- stringr::str_trim(summary)
  summary <- stringr::str_to_lower(summary)
  summary <- stringr::str_replace(summary, "_mean$", "_means")
  stopifnot(summary %in% c("annual_means", "monthly_means"))
  
  # Default files
  if (is.na(file[1]) && summary == "annual_means") {
    file <- "http://aq-data.ricardo-aea.com/R_data/saqgetr/observations_summaries/annual_mean_summaries.csv.gz"
  } else if (is.na(file[1]) && summary == "monthly_means") {
    file <- "http://aq-data.ricardo-aea.com/R_data/saqgetr/observations_summaries/monthly_mean_summaries.csv.gz"
  }
  
  # Set data types
  col_types <- readr::cols(
    date = readr::col_character(),
    date_end = readr::col_character(),
    site = readr::col_character(),
    variable = readr::col_character(),
    summary_source = readr::col_integer(),
    summary = readr::col_integer(),
    count = readr::col_double(),
    value = readr::col_double()
  )
  
  # Read data
  df <- read_csv_gz_remote(file, col_types = col_types) 
  
  # Parse dates
  if (nrow(df) >= 1) {
    df <- df %>% 
      mutate(date = lubridate::ymd_hms(date, tz = tz),
             date_end = lubridate::ymd_hms(date_end, tz = tz))
  }
  
  return(df)
  
}