Can Graphics Layers be Queried?

[ChristopherSchreiber]

Hello,

Can Graphics Layers be Queried?  I cannot see anywhere that says that they cannot.

I know that CSV Layers cannot be queried.

Thanks,

Chris

[RobertScheitlin__GISP]

Chris,

  The simple answer is No. But you could manually query the GL by looping through it's graphics and checking the graphics attributes.

[ThomasSolow · Accepted solution]

In the 4.XX API a layer view can be queried for a graphics layer the same way you would query the layer view for a feature layer: 

// source: https://developers.arcgis.com/javascript/latest/api-reference/esri-layers-FeatureLayer.html
// returns all the graphics from the layer view
view.whenLayerView(lyr).then(function(lyrView){
  lyrView.watch("updating", function(val){
    if(!val){  // wait for the layer view to finish updating
      lyrView.queryFeatures().then(function(results){
        console.log(results);  // prints all the client-side graphics to the console
      });
    }
  });
});‍‍‍‍‍‍‍‍‍‍‍

You could pass a Query into layerView.queryFeatures with an extent geometry and the 'intersects' spatial relationship to query for features inside an extent.  See Query | API Reference | ArcGIS API for JavaScript 4.3  for more details.

If you're using the 3.XX API, my bet would be that you could easily write a query method yourself by accessing each graphic in a graphics layer and using the geometry engine to test each one.  This is not an approach that scales especially well.  I'm not sure if layerView.queryFeatures scales very well either.

[ChristopherSchreiber]

Thank you all for the feedback!

[RyanSutcliffe]

I could be wrong but I don't see how you can get a LayerView class from a GraphicsLayer. Seems a GraphicsLayer creates a GraphicsLayerView which only has queryGraphics(). The example and link above works only for a FeatureLayer. If either of you were indeed able to do the above would love to see a code sample of how you got this: specifically a LayerView from a GraphicsLayer in a map. 

[RyanSutcliffe]

Taking a second look this morning I see how you can take a collection of graphics and set them as a source for a new FeatureLayer. That way you have access to queryFeatures and related functionality. I thought that a FeatureLayer required a REST endpoint or Map/FeatureService as it's source.