GeoJsonDataSource.loadUrl() and getDynamicObjectCollection()

CesiumJS
1

Hi all,

I’m running into an issue after loading a geoJSON from PostGIS.

Here’s the geoJSON I’m loading:

{
“type”: “FeatureCollection”,
“features”: [
{
“type”: “Feature”,
“geometry”: {
“type”:“Polygon”,
“coordinates”: [
[
[-74.0392315441728,40.7418578982759],
[-74.0392315441728,40.7055751656336],
[-73.9940771575758,40.7055751656336],
[-73.9940771575758,40.7418578982759],
[-74.0392315441728,40.7418578982759]
]
]
},
“properties”: {
“id”: 2,
“people”: 7000
}
},
{
“type”: “Feature”,
“geometry”: {
“type”:“Polygon”,
“coordinates”:[
[
[-73.9940771575758,40.7418578982759],
[-73.9940771575758,40.7055751656336],
[-73.9489227709788,40.7055751656336],
[-73.9489227709788,40.7418578982759],
[-73.9940771575758,40.7418578982759]
]
]
},
“properties”: {
“id”: 3,
“people”: 6933
}
}
]
}

From this, I want to take the ‘people’ property of each polygon created and create a label over top of the polygon. However, I can’t seem to get to the list of DynamicObjects created. Here’s my JS trying to just get a list of the objects:

function loadLandscan(lat, lon) {
var url = webapp_url +
‘/loadLandscan?lat=’ + encodeURIComponent(lat) +
‘&lon=’ + encodeURIComponent(lon);
var geoJsonSource = new Cesium.GeoJsonDataSource();
geoJsonSource.loadUrl(url);

    console.log(geoJsonSource.getDynamicObjectCollection());  // Print dynamicObjectCollection

console.log(geoJsonSource.getDynamicObjectCollection().getObjects()); // Print objects in dynamicObjectCollection
viewer.dataSources.add(geoJsonSource);
}

The dynamicObjectCollection looks full from the console output of

DynamicObjectCollection {_objects: AssociativeArray, _addedObjects: AssociativeArray, _removedObjects: AssociativeArray, _suspendCount: 0, _collectionChanged: Event…}
_addedObjects: AssociativeArray
_collectionChanged: Event
_id: “ce669254-1e15-46ba-9bf9-334e3ae6f1c9”
_objects: AssociativeArray
_array: Array[2]
0: DynamicObject
1: DynamicObject
length: 2
proto: Array[0]
_hash: Object
length: (…)
values: (…)
proto: Object
_removedObjects: AssociativeArray
_suspendCount: 0
collectionChanged: (…)
id: (…)
proto: Object

However, when printing the .getObjects() function, I’m getting an empty array.

Any idea why? Thanks in advance.

2

loadUrl operates asynchronously, so it hasn’t finished yet. Try:

var geoJsonSource = new Cesium.GeoJsonDataSource();

geoJsonSource.loadUrl(url).then(function() {

console.log(geoJsonSource.getDynamicObjectCollection().getObjects());

});

viewer.dataSources.add(geoJsonSource);