R/read_metro_area.R

In geobr: Download Official Spatial Data Sets of Brazil

#' Download spatial data of official metropolitan areas in Brazil
#'
#' @description
#' The function returns the shapes of municipalities grouped by their respective
#' metro areas. Metropolitan areas are created by each state in Brazil. The data
#' set includes the municipalities that belong to all metropolitan areas in the
#' country according to state legislation in each year. Original data were
#' generated by the Brazilian Institute of Geography and Statistics (IBGE). Data
#' at scale 1:250,000, using Geodetic reference system "SIRGAS2000" and CRS(4674).
#'
#' @template year
#' @template code_state
#' @template simplified
#' @template output
#' @template showProgress
#' @template cache
#' @template verbose
#'
#' @return An `"sf" "data.frame"` OR an `ArrowObject`
#'
#' @export
#'
#' @examplesIf identical(tolower(Sys.getenv("NOT_CRAN")), "true")
#' # Read all official metropolitan areas for a given year
#' m <- read_metro_area(year = 1970)
#'
#' m <- read_metro_area(
#'   year = 2024,
#'   code_state = "RJ"
#'   )
#'
read_metro_area <- function(year,
                            code_state = "all",
                            simplified = TRUE,
                            output = "sf",
                            showProgress = TRUE,
                            cache = TRUE,
                            verbose = TRUE){

  # Get metadata
  temp_meta <- select_metadata(
    geography = "metroarea",
    year = year,
    simplified = simplified,
    verbose = verbose
  )

  # check if download failed
  if (is.null(temp_meta)) { return(invisible(NULL)) }

  # download file and open arrow dataset
  temp_arrw <- download_parquet(
    filename_to_download = temp_meta$file_name,
    showProgress = showProgress,
    cache = cache
  )

  # check if download failed
  if (is.null(temp_arrw)) { return(invisible(NULL)) }

  # FILTER
  temp_arrw <- filter_arrw(temp_arrw, code = code_state)

  # convert to sf
  temp <- convert_output(temp_arrw, output)

  return(temp)
}