topic Re: Identify on FeatureLayer using Coordinates in ArcGIS API for Flex Questions

Identify on FeatureLayer using Coordinates

Anonymous User — Tue, 26 Apr 2011 14:59:23 GMT

All of the examples/samples I've seen dealing with FeatureLayers and Identify deal with mouse clicks. Is there a way to do the same with a coordinate passed from, say, an address locator?

Thanks!

rGibson

Re: Identify on FeatureLayer using Coordinates

RobertScheitlin__GISP — Tue, 26 Apr 2011 15:08:13 GMT

Russell,

Sure if you look at the code the only thing the mouse click is doing is getting some geometry to use for the identifyTask.

Re: Identify on FeatureLayer using Coordinates

Anonymous User — Tue, 26 Apr 2011 15:10:49 GMT

I guess in the samples, I'm missing where the coordinate from the click is being passed to the FeatureServer. Does the FeatureServer inheritently listen for a map click?

Thanks!

r

Re: Identify on FeatureLayer using Coordinates

Anonymous User — Tue, 26 Apr 2011 15:12:19 GMT

I'm not using a MapServer, rather a FeatureServer. And in the FeatureServer samples there is no use of an identifyTask. At least in the Esri online Samples, that is.

r

Re: Identify on FeatureLayer using Coordinates

RobertScheitlin__GISP — Tue, 26 Apr 2011 15:14:17 GMT

Russell,

Oh... If you are talking about a FeatureLayer than the info window that is poped up when you click on the feature has nothing to do with the identifyTask. Is that what you are talking about?

Re: Identify on FeatureLayer using Coordinates

Anonymous User — Tue, 26 Apr 2011 15:27:43 GMT

Russell,

Oh... If you are talking about a FeatureLayer than the info window that is poped up when you click on the feature has nothing to do with the identifyTask. Is that what you are talking about?

Exactly. Can you run an identifyTask on a FeatureLayer as you would a MapService layer?

Thanks

Re: Identify on FeatureLayer using Coordinates

RobertScheitlin__GISP — Tue, 26 Apr 2011 15:33:09 GMT

Russell,

You can but... What is your end game??? The identify task is suited for clicking on a map and having it return results from all map services that are included in that map including featureLayers. If you are just trying to get specific info about the actual feature (graphic) that you click on then why not just use the info window or the new 2.3 PopUpInfo?

Re: Identify on FeatureLayer using Coordinates

Anonymous User — Tue, 26 Apr 2011 15:41:23 GMT

Russell,

You can but... What is your end game??? The identify task is suited for clicking on a map and having it return results from all map services that are included in that map including featureLayers. If you are just trying to get specific info about the actual feature (graphic) that you click on then why not just use the info window or the new 2.3 PopUpInfo?

Right. I want to pass the coordinates returned from an address locator into multiple layers of a featureService. I have done so successfully using MapServices but was going to try using a featureService. So can u use the URL of a featureService in an identifyTask?

Thanks again.

Re: Identify on FeatureLayer using Coordinates

RobertScheitlin__GISP — Tue, 26 Apr 2011 15:50:08 GMT

Russell,

The documentation says

URL to the ArcGIS Server REST resource that represents a map layer

So I would say yes.

Re: Identify on FeatureLayer using Coordinates

Anonymous User — Tue, 26 Apr 2011 20:47:16 GMT

Hmmmm...oddly enough, if I simply plug in the URL of a FeatureService in the identifyTask, the identifyTask hangs. All reference systems are identical between the map, locator service and the feature service. Let you know what I find out. Thanks!

r

Re: Identify on FeatureLayer using Coordinates

IvanBespalov — Wed, 27 Apr 2011 05:13:19 GMT

Sorry, but I do not understand why IdentifyTask needed?

1 - FeatureLayer has default MXML property graphicProvider= ArrayCollection of all the graphics currently in the layer. Each of graphics has geometry.
2 - FeatureLayer has public property outFields.
3 - Well - you have array of geometries(graphicProvider) on client side and fields(outFields) on client side. Tell me why new server call(IdentifyTask) needed? Or I'm missing something?

Thanks.

Re: Identify on FeatureLayer using Coordinates

Anonymous User — Wed, 27 Apr 2011 05:30:15 GMT

Sorry, but I do not understand why IdentifyTask needed?

1 - FeatureLayer has default MXML property graphicProvider= ArrayCollection of all the graphics currently in the layer. Each of graphics has geometry.
2 - FeatureLayer has public property outFields.
3 - Well - you have array of geometries(graphicProvider) on client side and fields(outFields) on client side. Tell me why new server call(IdentifyTask) needed? Or I'm missing something?

Thanks.

Hi, Ivan.

Desire is to use point coordinates from address locator to perform point-in-polygon analysis. IdentityTask is the only way I am familiar with.

Re: Identify on FeatureLayer using Coordinates

Anonymous User — Wed, 27 Apr 2011 05:36:02 GMT

Sorry, but I do not understand why IdentifyTask needed?

1 - FeatureLayer has default MXML property graphicProvider= ArrayCollection of all the graphics currently in the layer. Each of graphics has geometry.
2 - FeatureLayer has public property outFields.
3 - Well - you have array of geometries(graphicProvider) on client side and fields(outFields) on client side. Tell me why new server call(IdentifyTask) needed? Or I'm missing something?

Thanks.

I might also add that the need is to simultaneously perform the identify/query on multiple polygon layers using the same coordinates. Possibly as many as 20. I've done this successfully using MapServices. Just trying it with FeatureService.

Re: Identify on FeatureLayer using Coordinates

IvanBespalov — Sat, 11 Dec 2021 13:26:33 GMT

OK, if I need to

Identify on FeatureLayer using Coordinates

, and this layer is <esri:Map /> child i do not make any calls to ArcGIS server, because FeatureLayer is the result of query and has all needed geometries and fields on client side. I'll just filter and sort it as I need:

for each (var gr:Graphic in featureLayer.graphicProvider)
{
    // find geometry and get fields
}

If I

Just trying it with FeatureService

not included in <esri:Map /> MXML tag. I call to server with new query.

MapServer - look for Supported Operations
FeatureServer - look for Supported Operations

Anywhere good luck.

Re: Identify on FeatureLayer using Coordinates

Anonymous User — Wed, 27 Apr 2011 12:50:04 GMT

Why an identifyTask? Because I could be querying as many as 20 separate layers and sorting through as many as 100 fields. In the app I query various polygon layers contained in MapServices dynamically based on the coordinate of an address, pulling just those values I need for the report to the user. Placing the FeatureLayer inside the Map tag would require listing everyone of those fields I would potentially need to query in the Outfields, correct?

So what I'm hearing is that you cannot (or shouldn't) place the URL of a FeatureService in the identifyTask MXML tag, correct?

r

Re: Identify on FeatureLayer using Coordinates

IvanBespalov — Thu, 28 Apr 2011 05:49:05 GMT

Placing the FeatureLayer inside the Map tag would require listing everyone of those fields I would potentially need to query in the Outfields, correct?

Yes. The same as if you make a QueryTask call to FeatureService.

So what I'm hearing is that you cannot (or shouldn't) place the URL of a FeatureService in the identifyTask MXML tag, correct?

No. May be because my English is too bad, I did not understand your post question.

1 - My mistake. Identify on FeatureLayer in your post header for "ArcGIS API for Flex" confused me. I think what you are talking about com.esri.ags.layers.FeatureLayer.

2 - FeatureService (//server/ArcGIS/rest/services/name/FeatureServer/layerID) Supported Operations are "Query" "Add Features" "Update Features" "Delete Features" "Apply Edits". No Identify supported.

Good luck.

Re: Identify on FeatureLayer using Coordinates

RobertScheitlin__GISP — Sat, 11 Dec 2021 13:26:36 GMT

Russell,

Here is a snippet of code from my Identify widget that shows how I handle FeatureService. The important part of the code is where I create a mapservice url from the featureservice url, most of the other stuff is specific to me determining which layers are visible.

if (layer is FeatureLayer)
     {
      var featLayer:FeatureLayer = layer as FeatureLayer;
      url = featLayer.url;
      var layId:int = -1;
      var arcDL:ArcGISDynamicMapServiceLayer;
      
      if( url.indexOf("FeatureServer") > -1)
      {
       var msName:String = url.replace("FeatureServer","MapServer");
       arcDL = new ArcGISDynamicMapServiceLayer(msName.substring(0,msName.lastIndexOf("/")));
       url = arcDL.url;
       layId = parseInt(msName.substring(msName.lastIndexOf("/")+ 1));
      }else{
       arcDL = new ArcGISDynamicMapServiceLayer(url.substring(0,url.lastIndexOf("/")));
       layId = parseInt(url.substring(url.lastIndexOf("/")+ 1));
       url = arcDL.url;
      }
      
      if(identifyLayerOption == "visible")
      {
       if(layId != -1)
        identifyParams.layerIds = [layId];
       if(featLayer.visible == false)
        url="";
      }
     }

Re: Identify on FeatureLayer using Coordinates

Anonymous User — Thu, 28 Apr 2011 15:04:16 GMT

First off, many thanks to Robert and Ivan for their efforts and patience. You guys are a real asset.

Here's what I found and it's actually due to a bug (NIM033079).....

When running an identifyTask on a FeatureService, the identifyTask will fail on non-visible layers. Oddly enough there is no problem doing the same with a garden-variety MapService. So in my code in the identifyParams setup I was using identifyParams.layerOption = IdentifyParameters.LAYER_OPTION_ALL. This was causing the issue. So according to ESRI, the work-around is to specify the layerOption as "top" or just do not specify any layer option.

Again, thanks for everyone's help.

Russell