使用谷歌的邮政编码距离

Question

我有两个邮政编码列表(在R中)...其中一个孩子的地址与他们的学业成绩和一个学校......

我希望能够为每个孩子获得最近的学校......所以大概是通过转换为长期和纬度值来计算邮政编码之间的距离？

然后我希望能够在谷歌地图上绘制每所学校的所有孩子......并看看住在离学校较近的孩子是否能获得更好的成绩......或许可以为孩子和孩子们设置不同颜色的学校根据他们的分数有一个渐变的颜色？

也许是使用googleVis包的东西？

所以例如......

如果我们有3个孩子和2所学校的数据......

student.data <- cbind(post.codes=c("KA12 6QE", "SW1A 0AA", "WC1X 9NT"),score=c(23,58,88))
school.postcodes <- c("SL4 6DW", "SW13 9JT")

(注意我的实际数据明显大于给定的数据,因此可扩展性很有用......)

应该怎么做googleVis或任何其他包,以便能够完成上述？

Answer 1

我会从这样的东西开始得到纬度/经度

获取每个邮政编码的纬度/经度

library(XML)
school.postcodes <- c("KA12 6QE", "SW1A 0AA", "WC1X 9NT")
ll <- lapply(school.postcodes,
    function(str){
       u <- paste('http://maps.google.com/maps/api/geocode/xml?sensor=false&address=',str)
       doc <-  xmlTreeParse(u, useInternal=TRUE)
       lat=xpathApply(doc,'/GeocodeResponse/result/geometry/location/lat',xmlValue)[[1]]
       lng=xpathApply(doc,'/GeocodeResponse/result/geometry/location/lng',xmlValue)[[1]]
       c(code = str,lat = lat, lng = lng)
})
# get long/lat for the students
ll.students <- lapply(student.data$post.codes,
             function(str){
               u <- paste('http://maps.google.com/maps/api/geocode/xml?sensor=false&address=',str)
               doc <-  xmlTreeParse(u, useInternal=TRUE)
               lat=xpathApply(doc,'/GeocodeResponse/result/geometry/location/lat',xmlValue)[[1]]
               lng=xpathApply(doc,'/GeocodeResponse/result/geometry/location/lng',xmlValue)[[1]]
               c(code = str,lat = lat, lng = lng)
             })

ll <- do.call(rbind,ll)
ll.students <- do.call(rbind,ll.students)

do.call(rbind,ll)
      code         lat          lng         
[1,] "KA12%206QE" "55.6188429" "-4.6766226"
[2,] "SW1A%200AA" "51.5004864" "-0.1254664"
[3,] "WC1X%209NT" "51.5287992" "-0.1181098"

得到距离矩阵

library(RJSONIO)
dist.list <- lapply(seq(nrow(ll)),
                    function(id){
                      url <- paste("http://maps.googleapis.com/maps/api/distancematrix/json?origins=",
                                   ll[id,2],",",ll[id,3],
                                   "&destinations=",
                                   paste( ll.students[,2],ll.students[,3],sep=',',collapse='|'),
                                   "&sensor=false",sep ='')
                      res <- fromJSON(url)
                        hh <- sapply(res$rows[[1]]$elements,function(dest){
                          c(distance= as.numeric(dest$distance$value),
                                     duration = dest$duration$text)
                        })
                      hh <- rbind(hh,destination =  ll.students[,1])

                    })
names(dist.list) <- ll[,1]

dist.list
$`SL4 6DW`
            [,1]              [,2]      [,3]     
distance    "664698"          "36583"   "41967"  
duration    "6 hours 30 mins" "43 mins" "49 mins"
destination "1"               "2"       "3"      

$`SW13 9JT`
            [,1]              [,2]      [,3]     
distance    "682210"          "9476"    "13125"  
duration    "6 hours 39 mins" "22 mins" "27 mins"
destination "1"               "2"       "3"