openrouteservice.org接口

Question

使用openrouteservice...

并在他们的wiki page上修改建议的url示例...

如果在浏览器中运行以下url ...

http://openrouteservice.org/index.php?start=7.0892567,50.7265543&end=7.0986258,50.7323634&lat=50.72905&lon=7.09574&zoom=15&pref=Fastest&lang=en

我得到了一条相关的路线...

但我想消除对浏览器的依赖，这样我就能够使用R以编程方式下载XML、路由配置文件和GPX (在左侧可用)，通过提供任何给定的经度/经度组合并在URL中添加适当的参数。

我的想法是将httr包与GET或POST命令一起使用，因为我不想使用RSelenium。

使用Google Chrome的inspect元素似乎不能产生清晰的URL...so，我不太确定如何开始这样做。

Answer 1

确定它(Chrome)支持…查找http://openrouteservice.org/php/OpenLSRS_DetermineRoute.php

library(httr)

params <- list(Start="7.0892567,50.7265543",
               End="7.0986258,50.7323634",
               Via="",
               lang="en",
               distunit="KM",
               routepref="Fastest",
               avoidAreas="",
               useTMC="",
               noMotorways="false",
               noTollways="false",
               instructions="true",
               `_`="")

resp <- POST("http://openrouteservice.org/php/OpenLSRS_DetermineRoute.php",
             body=params, encode="form")

content(resp)

## <xls:XLS xmlns:xls="http://www.opengis.net/xls" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:gml="http://www.opengis.net/gml" version="1.1" xsi:schemaLocation="http://www.opengis.net/xls http://schemas.opengis.net/ols/1.1.0/RouteService.xsd">
##   <xls:ResponseHeader xsi:type="xls:ResponseHeaderType"/>
##   <xls:Response xsi:type="xls:ResponseType" requestID="123456789" version="1.1" numberOfResponses="1">
##     <xls:DetermineRouteResponse xsi:type="xls:DetermineRouteResponseType">
##       <xls:RouteSummary>
##         <xls:TotalTime>PT2M39S</xls:TotalTime>
##         <xls:TotalDistance uom="KM" value="2.2"/>
##         <xls:BoundingBox srsName="EPSG:4326">
##           <gml:pos>7.0892519 50.7254372</gml:pos>
##           <gml:pos>7.1039336 50.7323788</gml:pos>
##         </xls:BoundingBox>
##       </xls:RouteSummary>
##       <xls:RouteGeometry>
##         <gml:LineString srsName="EPSG:4326">
##           <gml:pos>7.0892567 50.7265543</gml:pos>
##           <gml:pos>7.089251870496228 50.72654506565571</gml:pos>
## ....

Answer 2

在openrouteservice包的帮助下，现在可以很容易地从R连接openrouteservice应用程序接口。不再需要手动构建查询！考虑以下示例，并查看包vignette以获取所提供功能的概述。

library(openrouteservice)

# one-time API key set-up
# ors_api_key("<your-api-key>")

# query for coordinates
locations <- lapply(c("Heidelberg", "Kraków"), ors_geocode)
coordinates <- lapply(locations, function(x) x$features[[1]]$geometry$coordinates)

# find route 
route <- ors_directions(coordinates, format="geojson")

# route length in kilometres and duration in hours
unlist(route$features[[1]]$properties$summary) / c(1000, 3600)
##    distance    duration
## 1051.861300    9.205167

# draw on map using leaflet
library(leaflet)

leaflet() %>%
  addTiles() %>%
  addGeoJSON(route, fill=FALSE) %>%
  fitBBox(route$bbox)

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