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javascriptjqueryd3.jsleaflet

Looping through JSON to grab geo-coordinates (d3 and leaflet)

I've asked this before but simplifying the question. I have a JSON with geo-coordinates that I'd like to map in d3/leaflet:

Here's the structure, when console.logging the JSON allSFEvents:

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

And digging into one item:

@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

When I try to convert to latLong coordinates:

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)
  })

It gives me an error saying:

Cannot read property 'geo' of undefined

How do I loop through each item and run the L/.LatLong here? I seem to be stuck. The goal is to get distinct lat/long pairs for each item, in order to map it. What can I try next?

Solution

  • the forEach-function goes thru every element of your list and the parameter of the function is the one item of the list. So d is one item of your allSFEvents-Array.

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

    So try the following:

    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)
  })