R/traveltime.R

In kjetilhaukas/gmapi:

#' Calculate travel time from ANY coordinate system
#'
#' Calculate travel time from coordinates via Google Maps API.
#' Can use any coordinate system. The default is "+proj=longlat +datum=WGS84"
#' which is the one Google Maps prefers. Requires a Google Maps dev key.
#'
#' @param x_start numeric vector of coordinates in any coordinate format
#' @param y_start numeric vector of coordinates in any coordinate format
#' @param x_end numeric vector of coordinates in any coordinate format
#' @param y_end numeric vector of coordinates in any coordinate format
#' @param mode mode in gmapdistance package, e.g. "driving".
#' @param crs the coordinate system (e.g. "+proj=utm +zone=32N +datum=WGS84")
#' @param key Google API key
#' @return data frame with travel time and distance
#' @examples
#' traveltime(x_start = 10.73426, y_start = 59.95023,
#' x_end = 10.74455, y_end = 59.95137,
#' mode = "driving", key = my_key)
traveltime <- function(x_start, x_end, y_start, y_end, crs = NULL, mode, key, silent = TRUE){

  library(gmapsdistance)
  library(dplyr)

  if(!is.null(crs)){
    start <- reproj(x_start, y_start, crs = crs) %>%
      select(-id)
    end <- reproj(x_end, y_end, crs = crs)
  } else {
    start <- data.frame(x = x_start, y = y_start)
    end <- data.frame(x = x_end, y = y_end)
  }

  st <- start %>%
    mutate(xy=paste0(y,"+",x))

  sl <- end %>%
    mutate(xy=paste0(y,"+",x))

  dist <- list()
  for(i in 1:nrow(start)){
    if(!silent){
      print(paste("start-end point", i))
    }
    dist[[length(dist) + 1]] <- gmapsdistance(origin = st$xy[i], destination = sl$xy[i],
                                              mode = mode, key = key)
  }

  time <- lapply(dist, `[[`, 1) %>% unlist()
  distance <- lapply(dist, `[[`, 2) %>% unlist()
  status <- lapply(dist, `[[`, 3) %>% unlist()

  start <- start %>%
    rename(start_x = x, start_y = y)

  end <- end %>%
    rename(end_x = x, end_y = y)

  df <- data.frame(start, end, time, distance, status)

  return(df)
}