使用 OpenStreetMap 和 R 搜索城市

Question

我想使用 R 中的 OpenStreetMap 获取列表中每个城市的 GPS 坐标。我的代码基于这个非常好 example。

唯一的区别是我想在city name和country code的基础上加上county name。下面是我的代码：

cities = data.frame(nom=c("Toulouse", "Paris", "Égletons", "Marseille", 
                          "Clermont Ferrand"), region=c("Haute-Garonne", "Paris", "Corrèze", 
                          "Bouches-du-Rhône", "Puy-de-Dôme"), pays=rep("FR",5))


locateCountry = function(nameCity, nameCounty, codeCountry) {
  cleanCityName = gsub(' ', '%20', nameCity)
  cleanCountyName = gsub(' ', '%20', nameCounty)
  url = paste(
    "http://nominatim.openstreetmap.org/search?city="
    , cleanCityName
    , "&county="
    , cleanCountyName
    , "&countrycodes="
    , codeCountry
    , "&limit=9&format=json"
    , sep="")
  resOSM = fromJSON(url)
  if(length(resOSM) > 0) {
    return(c(resOSM[[1]]$lon, resOSM[[1]]$lat))
  } else return(rep(NA,2)) 
}

coords <- t(apply(cities, 1, function(aRow) locateCountry(aRow[1], aRow[2])))

不幸的是，我收到以下消息：

Error in paste("http://nominatim.openstreetmap.org/search?city=", cleanCityName,  : 
  argument "codeCountry" is missing, with no default

我也在寻找一种方法来合并提取的坐标 coords 和 cities。

有人能帮忙吗？

Answer 1

答案：

library(OpenStreetMap)
library(RJSONIO)


cities = data.frame(nom=c("Toulouse", "Paris", "Égletons", "Marseille", 
                          "Clermont Ferrand"), region=c("Haute-Garonne", "Paris", "Corrèze", 
                          "Bouches-du-Rhône", "Puy-de-Dôme"), pays=rep("FR",5),
                    effectif=c(20,5,15,3,3))
print(cities)

locateCountry = function(nameCity, nameCounty, codeCountry) {
  cleanCityName = gsub(' ', '%20', nameCity)
  cleanCountyName = gsub(' ', '%20', nameCounty)
  url = paste(
    "http://nominatim.openstreetmap.org/search?city="
    , cleanCityName
    , "&county="
    , cleanCountyName
    , "&country="
    , "FR"
    , "&limit=9&format=json"
    , sep="")
  resOSM = fromJSON(url)
  if(length(resOSM) > 0) {
    return(c(resOSM[[1]]$lon, resOSM[[1]]$lat))
  } else return(rep(NA,2)) 
}

coords <- t(apply(cities, 1, function(aRow) locateCountry(aRow[1], aRow[2])))

cities$lat <- coords[,1]
cities$lon <- coords[,2]

使用 OpenStreetMap 和 R 搜索城市

Search cities using OpenStreetMap and R

r

openstreetmap