topic Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible in ArcGIS JavaScript Maps SDK Questions

JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

MaximeDemers — Sat, 11 Dec 2021 22:11:16 GMT

Hi!

Is it normal that the IdentifyTask returns features even if the layer is not visible? I see in the documentation that the layerOption parameter in the IdentifyParameters should define if the IdentifyTask will return feature for visibile layer only. However, this parameter seem not working. The popup is displayed even if the layer is not visible as shown below. The image and code below are taken from the documentation sample codes

 <script>
    require([
      "esri/Map",
      "esri/views/MapView",
      "esri/layers/TileLayer",
      "esri/tasks/IdentifyTask",
      "esri/tasks/support/IdentifyParameters",
      "dojo/_base/array",
      "dojo/on",
      "dojo/dom",
      "dojo/domReady!"
    ], function(
      Map, MapView, TileLayer,
      IdentifyTask, IdentifyParameters,
      arrayUtils, on, dom
    ) {

      var identifyTask, params;

      // URL to the map service where the identify will be performed
      var soilURL =
        "https://services.arcgisonline.com/arcgis/rest/services/Specialty/Soil_Survey_Map/MapServer";

      // Add the map service as a TileLayer for fast rendering
      // Tile layers are composed of non-interactive images. For that reason we'll
      // use IdentifyTask to query the service to add interactivity to the app
      var parcelsLyr = new TileLayer({
        url: soilURL,
        opacity: 0.85,
        visible: false
      });

      var map = new Map({
        basemap: "osm"
      });
      map.add(parcelsLyr);

      var view = new MapView({
        map: map,
        container: "viewDiv",
        center: [-120.174, 47.255],
        zoom: 7
      });

      view.then(function() {
        // executeIdentifyTask() is called each time the view is clicked
        on(view, "click", executeIdentifyTask);

        // Create identify task for the specified map service
        identifyTask = new IdentifyTask(soilURL);

        // Set the parameters for the Identify
        params = new IdentifyParameters();
        params.tolerance = 3;
        params.layerIds = [0, 1, 2];
        params.layerOption = "top";
        params.width = view.width;
        params.height = view.height;
      });

      // Executes each time the view is clicked
      function executeIdentifyTask(event) {
        // Set the geometry to the location of the view click
        params.geometry = event.mapPoint;
        params.mapExtent = view.extent;
        dom.byId("viewDiv").style.cursor = "wait";

        // This function returns a promise that resolves to an array of features
        // A custom popupTemplate is set for each feature based on the layer it
        // originates from
        identifyTask.execute(params).then(function(response) {

          var results = response.results;

          return arrayUtils.map(results, function(result) {

            var feature = result.feature;
            var layerName = result.layerName;

            feature.attributes.layerName = layerName;
            if (layerName === 'Soil Survey Geographic') {
              feature.popupTemplate = { // autocasts as new PopupTemplate()
                title: "{Map Unit Name}",
                content: "<b>Dominant order:</b> {Dominant Order} ({Dom. Cond. Order %}%)" +
                  "<br><b>Dominant sub-order:</b> {Dominant Sub-Order} ({Dom. Cond. Suborder %}%)" +
                  "<br><b>Dominant Drainage Class:</b> {Dom. Cond. Drainage Class} ({Dom. Cond. Drainage Class %}%)" +
                  "<br><b>Farmland Class:</b> {Farmland Class}"
              };
            }
            else if (layerName === 'State Soil Geographic') {
              feature.popupTemplate = { // autocasts as new PopupTemplate()
                title: "{Map Unit Name}",
                content: "<b>Dominant order:</b> {Dominant Order} ({Dominant %}%)" +
                  "<br><b>Dominant sub-order:</b> {Dominant Sub-Order} ({Dominant Sub-Order %}%)"
              };
            }
            else if (layerName === 'Global Soil Regions') {
              feature.popupTemplate = { // autocasts as new PopupTemplate()
                title: layerName,
                content: "<b>Dominant order:</b> {Dominant Order}" +
                  "<br><b>Dominant sub-order:</b> {Dominant Sub-Order}"
              };
            }
            return feature;
          });
        }).then(showPopup); // Send the array of features to showPopup()

        // Shows the results of the Identify in a popup once the promise is resolved
        function showPopup(response) {
          if (response.length > 0) {
            view.popup.open({
              features: response,
              location: event.mapPoint
            });
          }
          dom.byId("viewDiv").style.cursor = "auto";
        }
      }
    });
  </script>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

ThomasSolow — Thu, 30 Mar 2017 15:01:23 GMT

By default it looks like identify is run on the top layer only, regardless of client layer visibility. You can change this using the identify params. For instance if you wanted to run identify only on visible layers, you could set the "layerOption" property on the params to "visible."

IdentifyParameters | API Reference | ArcGIS API for JavaScript 4.3

If you want to get specific about which layers to query, you can pass an array of layerIds in as the "layerIds" property.

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

MaximeDemers — Thu, 30 Mar 2017 15:08:56 GMT

Thats not what the doc says about the layerOption "top" paramerer: Only the top-most VISIBLE layer is identified.

Anyway setting the layerOption to "visible" does not make any difference. You can try directly in the sample code sandbox

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

KenBuja — Sat, 11 Dec 2021 22:11:19 GMT

What you'll have to do is set the layerIds property to -1 (setting it to "[]" doesn't work, like it did in 3.x)

params = new IdentifyParameters();
params.tolerance = 3;
params.layerIds = [-1];
params.layerOption = "top";
params.width = view.width;
params.height = view.height;‍‍‍‍‍‍‍‍‍‍‍‍

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

MaximeDemers — Thu, 30 Mar 2017 15:19:39 GMT

Doing that, it wont work when the layer is visible...

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

KenBuja — Sat, 11 Dec 2021 22:11:22 GMT

So what you'll have to do is put a little code in to determine whether the layer is visible

if (parcelsLyr.visible) {
  params.layerIds = [0,1,2];
} else {
  params.layerIds = [-1];
}‍‍‍‍‍

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

MaximeDemers — Thu, 30 Mar 2017 15:31:21 GMT

Imagine you have more than one layer that you want to use with the IdentifyTask, for instance subLayers in a MapImageLayer, you wont be able to use such workaround.

It seems to be a bug in the API right?

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

KenBuja — Thu, 30 Mar 2017 15:58:52 GMT

Yes, it does seem to be a bug. However, I'm not sure why you couldn't simply determine which layers are visible and use that in the layerIds property. For example, in the sandbox example, if I use

params.layerIds = [1];

then I get the result at the initial zoom level, but not when I zoom in or out far enough where the visible map changes from "State Soil Geographic" to "Soil Survey Geographic" or "Global Soil Regions"

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

ThomasSolow — Thu, 30 Mar 2017 16:08:43 GMT

I'd consider it a bug since "visible" doesn't appear to be working, and the documentation for "top" appears to be wrong.

It's not clear to me what a layer id is in this situation. You should be able to use Collection.flatten to get all layers + all sublayers and then map that to a list of ids. But what does [0,1,2] refer to here? Are those ids just "index of layer?"

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

MaximeDemers — Thu, 30 Mar 2017 16:18:16 GMT

According to me, the layerIds property refer to the subLayers ids (see for instance MapImageLayer.subLayers in the documentation.) When you instantiate an IdentifyTask(), you give the url of the layer that would be queried by the tool. So, layerIds is not related to every layers in the map, only the subLayers of the layer you have initiate the IdentifyTask with.

How is possible that no one have ever encountered this bug before? I can't believe it. I think it would be trivial to fix it, but how long shall we wait for the fix?

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

ThomasSolow — Sat, 11 Dec 2021 22:11:24 GMT

It's of course possible that someone else has encountered this bug. For the time being, though, I think there is probably an acceptable workaround.

For example, if we only have to worry about one layer, or the sublayers of one layer, we could try something like this:

      function getVisibleLayerIds(map, layer){
        if (layer.sublayers){
          return layer.sublayers.filter(sublayer => sublayer.visible).map(sublayer => layer.sublayers.indexOf(sublayer));
        } else {
          return layer.visible ? [map.allLayers.indexOf(layer)] : [-1];
        }
      }‍‍‍‍‍‍‍

This could be calculated on click and the result could be passed into the layerId property of IdentifyParams.

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

MaximeDemers — Thu, 30 Mar 2017 16:45:42 GMT

Thank you for your help Thomas. I have already tried this workaround. It could works only if you don't use definitionExpression on the subLayers, what I do.

The features in subLayers that are invisible by the action of the definitionExpression are queried anyway by the IdentifyTask().

I don't think there is a workaround that will cover every possibilities...

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

hoogw — Wed, 17 Jul 2019 18:28:21 GMT

your code, getVisibleLayerIds(), NOT work.

it suppose return array [2, 4, 6],

but it actually return empty array []

Please fix the bug

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

hoogw — Fri, 19 Jul 2019 16:04:12 GMT

Your code only works for single level sublayers, DOES NOT work when multiple level of sublayers,

For example, a sublayers have children sublayers, etc.... 2 level deep sulayers.....

You have to use recursive to solve the multiple deep level sublayers.....

Here is my working code:

var _current_visible_layer_id_array = []

// you call this method

recursive_nestedLayer(map,_map_image_layer.sublayers);

// then you set

params.layerIds = _current_visible_layer_id_array

// now it works.

// *********************** get current visible layer ***********************

/*
// https://community.esri.com/thread/192627-jsapi-v43-identifytask-returns-feature-even-if-layer-is-not-visible
// only works when layer NOT have nest sublayers. Only 1 level,
function getVisibleLayerIds(map, layer){
if (layer.sublayers){
return layer.sublayers.filter(sublayer => sublayer.visible).map(sublayer => layer.sublayers.indexOf(sublayer));
} else {
return layer.visible ? [map.allLayers.indexOf(layer)] : [-1];
}
}
*/

// for nested sublayer, use recursive
function recursive_nestedLayer(map, _nestedLayer){

_nestedLayer.forEach(function(item, i){

if (item.sublayers){

// recursive function deep 1 level
recursive_nestedLayer(map, item.sublayers);
}else {

console.log('-low-level-item',item )

if (item.visible){

console.log("visible !!!!")

// map.allLayers.indexOf(item), not work, maybe lost layer handle, instead use item.id works.
//_current_visible_layer_id_array.push(map.allLayers.indexOf(item));
_current_visible_layer_id_array.push(item.id);
} else {

_current_visible_layer_id_array.push(-1);

}

} // if

});

} //recursive_nestedLayer

// *********************** end ********************** get current visible layer ***********************

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

hoogw — Fri, 19 Jul 2019 20:35:02 GMT

now I found a better way:

you call:

// .allSublayers is a flat collection of all children layer, including parent folder
_current_visible_layer_id_array = getVisibleLayerIds(_map_image_layer.allSublayers);

function getVisibleLayerIds(flat_layer_collection){

// layer is collection of all kinds of layers. find the visible one

var ___array = [];
flat_layer_collection.forEach(function(item, i){

console.log("flat_collection_forEach - item: ====== >",item )

if (item.sublayers) {
// if item.sublayers is NOT null, means, item have children sulayer or layers.
// filter out

} else {
// sublayer is null
if (item.visible) {

___array.push(item.id);
} else {

___array.push(-1);

}

}
});

return ___array;
} // getVisibleLayerIds

Re: JSAPI v4.3 - IdentifyTask returns feature even if layer is not visible

NilsBabel1 — Thu, 31 Dec 2020 17:23:01 GMT

Did you ever log a bug with Esri on this? This seems to still be an issue at 4.17. Although, I wonder if it is a bug or a flaw in the logic. When creating a new IdentifyTask you just specify a url. It isn't really tied to the layer at all. So how would it know if the layer is visible or not? It seems like we are missing something.