R/otp-geocode.R

In marcusyoung/opentripplanner: Open Trip Planner for R

#'  Use OTP Geocoder to find a location
#'
#'  Geocoding converts a named place, such as a street name into a lat/long pair.
#'
#' @param otpcon OTP connection object produced by otp_connect()
#' @param query Character, The query string we want to geocode
#' @param autocomplete logical Whether we should use the query string to do a prefix match, default FALSE
#' @param stops Logical, Search for stops, either by name or stop code, default TRUE
#' @param clusters Logical, Search for clusters by their name, default FALSE
#' @param corners Logical, Search for street corners using at least one of the street names, default TRUE
#' @param type Character, How should results be returned can be "SF" or "Coordinates" or "Both", Default "SF"
#'
#' @return
#' Returns a data.frame of SF POINTS or Coordinates of all the locations that match `query`
#' @examples \dontrun{
#' locations <- otp_geocode(otpcon, "High Street")
#' }
#' @details
#' OTP will return a maximum of 10 results
#'
#' @export
otp_geocode <- function(otpcon = NA,
                        query = NA,
                        autocomplete = FALSE,
                        stops = TRUE,
                        clusters = FALSE,
                        corners = TRUE,
                        type = "SF")
{
  # Validate Inputs
  checkmate::assert_class(otpcon, "otpconnect")
  checkmate::assert_character(query)
  checkmate::assert_logical(autocomplete)
  checkmate::assert_logical(stops)
  checkmate::assert_logical(clusters)
  checkmate::assert_logical(corners)
  checkmate::assert_choice(type, choices = c("SF", "Coordinates", "Both"))


  autocomplete <- tolower(as.character(autocomplete))
  stops <- tolower(as.character(stops))
  clusters <- tolower(as.character(clusters))
  corners <- tolower(as.character(corners))

  # Construct URL
  routerUrl <- make_url(otpcon)
  routerUrl <- paste0(routerUrl, "/geocode")

  querylist <- list(
    query = query,
    autocomplete = autocomplete,
    stops = stops,
    clusters = clusters,
    corners = corners
  )

  req <- httr::GET(routerUrl,
                   query = querylist)

  # convert response content into text
  text <- httr::content(req, as = "text", encoding = "UTF-8")

  if (nchar(text) == 2) {
    warning(paste0("Failed to find '", query, "'"))
    return(NA)
  } else{
    # parse text to json
    asjson <- jsonlite::fromJSON(text)
    # parse to sf
    if (type %in% c("SF", "Both")) {
      if (type == "SF") {
        remove <- TRUE
      } else{
        remove <- FALSE
      }
      response = sf::st_as_sf(asjson,
                              coords = c("lng", "lat"),
                              remove = remove)
      return(response)
    } else{
      return(ajson)
    }

  }

}