Get extent from KML layer in ArcGIS Online

Question

Is there any way to calculate the extent of a KML layer loaded from the web using the KMLLayer({ url: "my file" }) method in ArcGIS Online? The KMLs loaded from AGOL have a valid fullExtent property, but ones loaded from other sources seem to default to the entire world, which is not useful.

Here is an example:

app.kml=new KMLLayer({ url: "my file" });                                                                                    
app.map.add(app.kml);                                                                                                    
app.kml.load().then(function() { app.mapView.extent=app.kml.fullExtent; console.log(app.kml) });

It is live at:

http://viseyes.org/visualeyes/test.htm?kml=https://www.arcgis.com/sharing/rest/content/items/a8efe6f4c12b462ebedc550de8c73e22/data

The console prints out the KMLLayer object, and the fullExtent field seems to be not set right.

Answer 1

I agree, it does not seem like the fullExtent property is what you would expect. I think there are two workarounds:

Write some code to query the layerView to get the extent:

view.whenLayerView(kmlLayer).then(function(layerView) {
  watchUtils.whenFalseOnce(layerView, "updating", function() {
    var kmlFullExtent = queryExtent(layerView);
    view.goTo(kmlFullExtent);
  });
});

function queryExtent(layerView) {
  var polygons = layerView.allVisiblePolygons;
  var lines = layerView.allVisiblePolylines;
  var points = layerView.allVisiblePoints;
  var images = layerView.allVisibleMapImages;

  var kmlFullExtent = polygons
    .concat(lines)
    .concat(points)
    .concat(images)
    .map(
      graphic => (graphic.extent ? graphic.extent : graphic.geometry.extent)
    )
    .reduce((previous, current) => previous.union(current));
  return kmlFullExtent;
}

Example here.

-- or --

Call the utility service again and use the "lookAtExtent" property:

view.whenLayerView(kmlLayer).then(function(layerView) {
  watchUtils.whenFalseOnce(layerView, "updating", function() {
    // Query the arcgis utility and use the "lookAtExtent" property -
    esriRequest('https://utility.arcgis.com/sharing/kml?url=' + kmlLayer.url).then((response) => {
      console.log('response', response.data.lookAtExtent);
      view.goTo(new Extent(response.data.lookAtExtent));
    });

  });
});

Example here.