0

我想制作一个闪亮的应用程序，它要求两个地址，映射一条有效的路线，并计算路线的总距离。这可以通过使用 javascript 库的Leaflet Routing Machine来完成，但是我想对路线的距离进行一些进一步的计算，并将其全部嵌入到闪亮的应用程序中。

您可以在此处按照 Ramnathv 的演示使用 rMaps 生成地图。但是即使我可以看到它已在图例或控制器中计算出来，我也无法得出总行驶距离。还有另一个关于如何使用 javascript 库执行此操作的讨论 - 请参见此处。他们讨论使用这个 javascript 代码：

alert('Distance: ' + routes[0].summary.totalDistance);

这是我的 rMap 工作代码。如果有人对如何提取路线的总距离并存储它有任何想法，我将不胜感激。谢谢！

# INSTALL DEPENDENCIES IF YOU HAVEN'T ALREADY DONE SO
library(devtools)
install_github("ramnathv/rCharts@dev")
install_github("ramnathv/rMaps")

# CREATE FUNCTION to convert address to coordinates
library(RCurl)
library(RJSONIO)

construct.geocode.url <- function(address, return.call = "json", sensor = "false") {
  root <- "http://maps.google.com/maps/api/geocode/"
  u <- paste(root, return.call, "?address=", address, "&sensor=", sensor, sep = "")
  return(URLencode(u))
}

gGeoCode <- function(address,verbose=FALSE) {
  if(verbose) cat(address,"\n")
  u <- construct.geocode.url(address)
  doc <- getURL(u)
  x <- fromJSON(doc)
  if(x$status=="OK") {
    lat <- x$results[[1]]$geometry$location$lat
    lng <- x$results[[1]]$geometry$location$lng
    return(c(lat, lng))
  } else {
    return(c(NA,NA))
  }
}

# GET COORDINATES
x <- gGeoCode("Vancouver, BC")
way1 <- gGeoCode("645 East Hastings Street, Vancouver, BC")
way2 <- gGeoCode("2095 Commercial Drive, Vancouver, BC")

# PRODUCE MAP
library(rMaps)
map = Leaflet$new()
map$setView(c(x[1], x[2]), 16)
map$tileLayer(provider = 'Stamen.TonerLite')

mywaypoints = list(c(way1[1], way1[2]), c(way2[1], way2[2]))

map$addAssets(
  css = "http://www.liedman.net/leaflet-routing-machine/dist/leaflet-routing-machine.css",
  jshead = "http://www.liedman.net/leaflet-routing-machine/dist/leaflet-routing-machine.js"
)

routingTemplate = "
 <script>
 var mywaypoints = %s
 L.Routing.control({
  waypoints: [
    L.latLng.apply(null, mywaypoints[0]),
    L.latLng.apply(null, mywaypoints[1])
  ]
 }).addTo(map);
 </script>"

map$setTemplate(
  afterScript = sprintf(routingTemplate, RJSONIO::toJSON(mywaypoints))
)
# map$set(width = 800, height = 800)
map
4

1 回答 1

1

您可以通过 google maps api 轻松创建路线。返回的数据帧将包含距离信息。只需总结总距离的腿。

library(ggmap)
x <- gGeoCode("Vancouver, BC")
way1txt <- "645 East Hastings Street, Vancouver, BC"
way2txt <- "2095 Commercial Drive, Vancouver, BC"
route_df <- route(way1txt, way2txt, structure = 'route')
dist<-sum(route_df[,1],na.rm=T) # total distance in meters
#
qmap(c(x[2],x[1]), zoom = 12) +
   geom_path(aes(x = lon, y = lat),  colour = 'red', size = 1.5, data = route_df, lineend = 'round')
于 2015-04-17T20:36:26.400 回答