Question

嗨，我有一系列的房屋和一系列的火车站。我想计算从每个家庭（n = 1718）到每个站（n = 11）的步行距离。我知道谷歌限制你每天2000张，所以我会做所有家庭的阻止1站。我的数据如下：

Home data:                      

        longitude   latitude            
    1   -76.27769   36.86308
    2   -76.29188   36.87556
    3   -76.26982   36.86628
    4   -76.27455   36.86894

    Station Data
        Longitude   Latitude
    1   -76.30377   36.85945
    2   -76.29490   36.85395
    3   -76.28896   36.85156
    4   -76.28989   36.84719
    5   -76.28579   36.84568

我找到了这样的代码，但它总结了每个家的距离，而不是每个家的距离。我对R来说很新...帮助！

  `distHoras <- function(origin, destination){

  origin <- gsub(",", "", origin)
  origin <- gsub(" ", "+", origin)
  origin <- paste("origins=", origin, sep = "")

  destination <- gsub(",", "", destination)
  destination <- gsub(" ", "+", destination)
  destination <- paste("destination=", paste(destination, 
                                               collapse = "|"), sep = "")


  mode4url <- paste("mode=", 'walking', sep = "")
  lang4url <- paste("language=", 'en-EN', sep = "")
  sensor4url <- paste("sensor=", tolower(as.character(FALSE)), 
                      sep = "")
  posturl <- paste(origin, destination, mode4url, sensor4url, 
                   sep = "&")
  url_string <- paste("http://maps.googleapis.com/maps/api/distancematrix/json?", 
                      posturl, sep = "")
  url_string <- URLencode(url_string)
  connect <- url(url_string)
  tree <- fromJSON(paste(readLines(connect), collapse = ""))
  close(connect)
  rapply(tree$rows,I)
}`

我得到像这样的输出

distHoras('origin', 'destination')
 elements.distance.text elements.distance.value 
             "1,253 km"               "1252635" 
 elements.duration.text elements.duration.value 
       "9 days 8 hours"                "804659" 
        elements.status 
                   "OK"

Answer 1

这样的东西？

google.dist <- function(from,to,mode="walking") {
  require(httr)
  require(XML)
  url    <- "https://maps.googleapis.com/maps/api/distancematrix/xml"
  origin <- paste(with(from,paste(latitude,longitude,sep=",")),collapse="|")
  dest   <- paste(with(to,paste(latitude,longitude,sep=",")),collapse="|")
  response <- GET(url,query=list(origins=origin,destinations=dest,mode=mode))
  doc      <- content(response,type="text/xml")
  status   <- sapply(doc["//row/element/status"],xmlValue)
  if(any(status!="OK")) warning("Error Status on some routes")
  distance <- sapply(doc["//row/element/distance/value"],xmlValue)
  data.frame(expand.grid(to=1:nrow(to),from=1:nrow(from)),distance=as.numeric(distance))
}
google.dist(Home,Station)
#    to from distance
# 1   1    1     3275
# 2   2    1     2494
# 3   3    1     2163
# 4   4    1     2548
# 5   5    1     2212
# 6   1    2     2539
# 7   2    2     2950
# 8   3    2     3288
# 9   4    2     3815
# 10  5    2     4034
# ...

这使用带有XML输出的Google Distance Matrix API。返回的数据框具有to和from数据帧的行号以及它们之间的距离（以米为单位）。该API已记录在案here。请仔细注意terms of use。

使用纬度和经度向量在R中查找步行距离

1 个答案: