R/strr_as_sf.R

In UPGo-McGill/strr: Tools for Analysis of Short-Term Rental Data

#' Function to convert property tables to sf objects
#'
#' \code{strr_as_sf} is a convenience wrapper around \code{\link[sf]{st_as_sf}}
#' for STR property tables.
#'
#' A function for converting a raw property table into an sf object with point
#' geometries. The function makes use of a pair of fields specifying longitude
#' and latitude, and has the option to specify a destination CRS.
#'
#' @param property A property table in standard UPGo format.
#' @param CRS The EPSG code or proj4string character vector specifying a
#' coordinate reference system into which to transform the table. The default
#' is unprojected WGS 84 (EPSG 4326).
#' @param longitude A character string naming the field supplying the
#' longitude values of points.
#' @param latitude A character string naming the field supplying the
#' latitude values of points.
#' @return An sf table with the longitude and latitude fields converted to a
#' geometry field and all other fields returned unaltered.
#' @export

strr_as_sf <- function(property, CRS = 4326, longitude = "longitude",
                       latitude = "latitude") {

  helper_check_property()

  property <- sf::st_as_sf(property, coords = c(longitude, latitude),
                           crs = 4326)
  property <- sf::st_transform(property, CRS)
  property <- sf::st_set_agr(property, "constant")

  property
}