Question

我之前曾问过这个问题，但是简化了这个问题。我有一个要在d3 /传单中映射的带有地理坐标的JSON：

这是控制台登录JSON allSFEvents时的结构：

(36) [{…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}]

并深入研究一项：

@context: "http://schema.org"
@type: "MusicEvent"
endDate: "2019-01-27"
image: ""
location:
    @type: "Place"
    address: "San Francisco, CA"
    geo:
        @type: "GeoCoordinates"
        latitude: 37.775
        longitude: -122.4183333
        __proto__: Object
    name: "Natoma Cabana"
    __proto__: Object
    name: "Winter Olympics"
    performer: {url: "https://www.bandsintown.com/a/217960- 
    winter-olympics?came_from=244", image: "", @type: 
   "MusicGroup", name: "Winter Olympics"}
startDate: "2019-01-27"
url: "https://www.bandsintown.com/e/1013280443-winter-olympics-at-natoma-cabana?came_from=244"
__proto__: Object

当我尝试转换为latLong坐标时：

allSFEvents.forEach(function(d) {

  d.latLong = new L.LatLng(allSFEvents.location.geo[0],//first position is latitude
              allSFEvents.location.geo[1];//second position is longitude
  console.log(d.latLong)
  })

这给了我一个错误：

Cannot read property 'geo' of undefined

如何遍历每个项目并在此处运行L / .LatLong？我似乎被困住了。目的是为每个项目获取不同的经/纬度对，以便进行映射。预先感谢。

Answer 1

forEach-function遍历列表的每个元素，并且该函数的参数是列表的一项。所以d是allSFEvents-Array的一项。

https://www.w3schools.com/jsref/jsref_forEach.asp

因此，请尝试以下操作：

allSFEvents.forEach(function(d) {

//here replace allSFEEvents with d then location should be set. And replace geo[0] with geo.latitude and geo[1] with geo.longitude because geo is not an array
  d.latLong = new L.LatLng(d.location.geo.latitude,//first position is latitude
              d.location.geo.longitude;//second position is longitude
  console.log(d.latLong)
  })

遍历JSON以获取地理坐标（d3和传单）

1 个答案: