topic Re: ESRI point clustering example using featurelayer or querytask as input? in ArcGIS JavaScript Maps SDK Questions

ESRI point clustering example using featurelayer or querytask as input?

TracySchloss — Fri, 05 Oct 2012 15:32:30 GMT

I have tried to implement the ESRI forum example for clustering "Clustering with Javascript API" http://www.arcgis.com/home/item.html?id=c546bc8d4f0b4c0fbdf149b92223e681 with mixed results. Sometimes the cluster layer draws fine and sometimes it doesn't draw at all. Even when it draws it's very slow and I'm not sure the users will be satisfied. There seems to be mixed reviews on this. The fact that it's display seem to be intermittent for me is enough for me to look to another clustering solution.

More recently, the ESRI sample "Point Clustering" was posted. http://help.arcgis.com/en/webapi/javascript/arcgis/help/jssamples_start.htm#jssamples/layers_point_clustering.html I like the way this looks, but I'm having a hard time understanding how to make it work with a layer as input, since my data is already in a service. It seems like either I should add a function to step through all my features to create properly formatted input data, or I should edit the custom layer to handle features of a featureset or featurelayer instead.

Has anyone modified ESRI's point clustering example to use something besides the input JSON file?

Re: ESRI point clustering example using featurelayer or querytask as input?

GordonBooth — Fri, 05 Oct 2012 16:59:43 GMT

Having the same problem. Please help.

Re: ESRI point clustering example using featurelayer or querytask as input?

derekswingley1 — Fri, 05 Oct 2012 17:09:00 GMT

One of the parameters for cluster layer is "data". As noted in the sample description, data is an array of objects and each object has the following properties: x, y and attributes.

Here's the workflow to get data from a layer in a map service or feature service in this format:

send a request to the layer's query endpoint with esri.request

when data comes back, use dojo.map to create an array of objects with x, y and attributes properties

pass the result from dojo.map to the cluster layer

That's a high level overview. Can one of you take a crack at coding it up and post back here? I can provide further help if you can't make it work.

Re: ESRI point clustering example using featurelayer or querytask as input?

StephenLead — Mon, 08 Oct 2012 00:53:29 GMT

Sometimes the cluster layer draws fine and sometimes it doesn't draw at all

Note that by default, ArcGIS Server only returns 1,000 features as a result of a query. In the problem above, it may be the case that you're zooming to an extent which doesn't contain any returned features (depending on how you're structuring the query).

Re: ESRI point clustering example using featurelayer or querytask as input?

TracySchloss — Tue, 09 Oct 2012 12:41:29 GMT

I"m not sure why I would use an esri.request to the query endpoint as opposed to executing a standard query task. I usually execute my query tasks with a callback to generate my featureset. Is is faster to request the data or formatted differently if I use esri.request instead?

Re: ESRI point clustering example using featurelayer or querytask as input?

derekswingley1 — Tue, 09 Oct 2012 14:30:45 GMT

I"m not sure why I would use an esri.request to the query endpoint as opposed to executing a standard query task. I usually execute my query tasks with a callback to generate my featureset. Is is faster to request the data or formatted differently if I use esri.request instead?

You could use a QueryTask to pull your features out. I said esri.request because it's always available (no additional modules to load) and you don't need any of Query's special functionality. I wouldn't expect a noticeable performance difference between the two.

Re: ESRI point clustering example using featurelayer or querytask as input?

TracySchloss — Sat, 11 Dec 2021 12:13:52 GMT

I'll just stick with my standard query task syntax then, which I'm more familiar with.

I'm getting stuck at the very beginning with the dojo.Config, which is generating an error in Aptana (version 2). I got this error when I loaded the sample too:

    <script> 
        var dojoConfig = {  
        parseOnLoad: true, 
        packages: [{ 
         "name": "extras", 
          "location": location.pathname.replace(/\/[^/]+$/, '') + "/extras" }] 
      }; 
</script>

The error:
Multiple items missing at this position:
missing ) after argument list
Bad regular expression:
\/[^/]+$/, '') + "/extras"

In the ESRI example, I changed this to have the location as just "/extras", which got rid of the error and then the sample ran.

When I made the same changes in my own code for dojo.Config, it errors on the line

dojo.require("extras,ClusterLayer);

The error in Firebug is 'url is undefined', which I take to mean it's not finding ClusterLayer.js after all.

I wouldn't call myself a novice programmer, but I am relatively new to JavaScript. I'm pretty comfortable with the coding of the functions, so probably the error toward the top. I don't know if my query task function is correct because it's not making it that far before it blows up!

Re: ESRI point clustering example using featurelayer or querytask as input?

TracySchloss — Tue, 09 Oct 2012 15:01:24 GMT

I see now that I still had all my references to version 2.5 of the API because that's what the forum post for clusters used. I changed my API references to 3.2 and I'm not getting the error on the dojo.require("extras.ClusterLayer").

The code still isn't working right, but at least I'm past the first error.

Re: ESRI point clustering example using featurelayer or querytask as input?

derekswingley1 — Tue, 09 Oct 2012 15:35:26 GMT

I see now that I still had all my references to version 2.5 <snip>

That will make a big difference. Glad you moved up to 3.2.

The code still isn't working right, but at least I'm past the first error.

Post the code you're currently using and a description of what isn't working?

Re: ESRI point clustering example using featurelayer or querytask as input?

TracySchloss — Tue, 09 Oct 2012 15:43:54 GMT

I can't believe I got it work! This method executes much faster than the forum example, so I'm glad I switched.

Here's the function that creates the cluster layer. I have an init function that calls it, and that is where infoTemplate is defined.

function runQuery(){     // layer 1 in the service contains all server locations and will be used to cluster     var queryTask = new esri.tasks.QueryTask("http://<myserver>/ArcGIS/rest/services/ITSD/serverLocations/MapServer/1");     var query = new esri.tasks.Query();     query.returnGeometry = true;     query.where = '1=1';     query.outFields = ["*"];          dojo.connect(queryTask, "onComplete", function(featureSet){         var inputInfo = {};         inputInfo.data = dojo.map(featureSet.features, function(feature){             var pointX = feature.geometry.x;             var pointY = feature.geometry.y;             var att = feature.attributes;             return {                 "x": pointX,                 "y": pointY,                 "attributes": att             };         });                  // cluster layer that uses OpenLayers style clustering          clusterLayer = new extras.ClusterLayer({             "data": inputInfo.data,             "distance": 100,             "id": "clusters",             "labelColor": "#fff",             "labelOffset": 10,             "resolution": map.extent.getWidth() / map.width,             "singleColor": "#888",             "singleTemplate": infoTemplate         });         var defaultSym = new esri.symbol.SimpleMarkerSymbol().setSize(4);         var renderer = new esri.renderer.ClassBreaksRenderer(defaultSym, "clusterCount");         var blue = new esri.symbol.PictureMarkerSymbol("http://static.arcgis.com/images/Symbols/Shapes/BluePin1LargeB.png", 32, 32).setOffset(0, 15);         var green = new esri.symbol.PictureMarkerSymbol("http://static.arcgis.com/images/Symbols/Shapes/GreenPin1LargeB.png", 64, 64).setOffset(0, 15);         var red = new esri.symbol.PictureMarkerSymbol("http://static.arcgis.com/images/Symbols/Shapes/RedPin1LargeB.png", 72, 72).setOffset(0, 15);         renderer.addBreak(0, 2, blue);         renderer.addBreak(2, 200, green);         renderer.addBreak(200, 1001, red);                  clusterLayer.setRenderer(renderer);         map.addLayer(clusterLayer);                  // close the info window when the map is clicked          // dojo.connect(map, "onClick", cleanUp);          // close the info window when esc is pressed          dojo.connect(map, "onKeyDown", function(e){             if (e.keyCode == 27) {                 cleanUp();             }         });         dojo.connect(queryTask, "onError", function(err){             alert(err.details);         });                       });     queryTask.execute(query); }

Re: ESRI point clustering example using featurelayer or querytask as input?

derekswingley1 — Tue, 09 Oct 2012 15:57:17 GMT

I can't believe I got it work! This method executes much faster than the forum example, so I'm glad I switched.

That's awesome! Glad you got it working.

Re: ESRI point clustering example using featurelayer or querytask as input?

TracySchloss — Tue, 09 Oct 2012 16:20:04 GMT

Do you have any thoughts on the error I'm getting in location.pathname.replace? It seems like I would be better of with this type of syntax instead of changing it to be more "hard coded".

Re: ESRI point clustering example using featurelayer or querytask as input?

Jay_Gregory — Fri, 01 Feb 2013 13:26:32 GMT

One question I have about this: is there any way to configure a cluster layer for a feature service so it isn't limited by the 1000 feature return limit on Server? It seems that one of the benefits of clustering would be being able to visualize total number of events in an area, even if the total events are greater than 1000.

Jay

Re: ESRI point clustering example using featurelayer or querytask as input?

derekswingley1 — Fri, 01 Feb 2013 15:54:27 GMT

One question I have about this: is there any way to configure a cluster layer for a feature service so it isn't limited by the 1000 feature return limit on Server? It seems that one of the benefits of clustering would be being able to visualize total number of events in an area, even if the total events are greater than 1000.

Change the limit on the server, or do multiple requests to retrieve your data before handing it off to the cluster layer.

Re: ESRI point clustering example using featurelayer or querytask as input?

muhammadalmas — Wed, 27 Feb 2013 19:21:05 GMT

Any chance of having 'flare effect' with this clustering (just like silverlight/flex counterpar)?

Re: ESRI point clustering example using featurelayer or querytask as input?

TracySchloss — Wed, 27 Feb 2013 19:25:57 GMT

Don't hold your breath. There is quite a bit of animation that easily used in FLEX that isn't there in JS. I actually started out with the FLEX version, but have had to move away from it because of lack of mobile support. Yes, I know it can be written as an app, but that's not a popular alternative in this office.

Re: ESRI point clustering example using featurelayer or querytask as input?

danbonab — Wed, 08 May 2013 16:49:47 GMT

I'm sorry but I don't care much for ClusterLayer. Clustering is a feature of a graphic based layer (esri.layers.GraphicsLayer).
Why should my layer lets say a featureLayer (which is a graphicsLayer subclass) morph into a different type of layer to display feature clusters? It doesn't make any sense!
Silverlight API got this right. In Silverlight, GraphicsLayer has a Clusterer property which encapsulates all the clustering logic, so if you need clustering you don't need to create a different type of layer and add it to the map.
Clustering in Silverlight happens when graphics are being added and you could easily extend the OnGraphicsAdded event handler to apply your own clustering logic or use existing FlareClusterer which works decently.
I'm not expecting all the flare animation, I'm aware of the challenges of that when it comes to running in different browsers, the only thing I'm expecting is a clusterer property for graphicsLayer and a defaultClusterer that would support basic clustering properties like maxFeatureCount, radius, and color.

Re: ESRI point clustering example using featurelayer or querytask as input?

StephenLead — Wed, 08 May 2013 19:50:54 GMT

a clusterer property for graphicsLayer and a defaultClusterer that would support basic clustering properties like maxFeatureCount, radius, and color.

+1, that would be very nice. Ideally it would work for a featureLayer too.

Re: ESRI point clustering example using featurelayer or querytask as input?

bdv_works — Tue, 13 Aug 2013 14:16:40 GMT

Hi, we did it through the server-side clustering solutions and use Esri js-apis to plot the JSON outputs;
pls see the app link:

http://www.bigdatavisulization.com:8...er_locate.html

// we can remove the house number when searching, which will give 70 million records on-the-fly...

Re: ESRI point clustering example using featurelayer or querytask as input?

BrianFischer — Wed, 30 Oct 2013 12:56:43 GMT

I noticed the link doesn't work, display's a blank map. Is there a different link to look at?

We have the clustering working well on 100,000+ points but noticed that when the cluster marker has more than 1000 count it drops the marker graphic and only displays the label. Is this a limitation of the Javascript api or a bug with it? Could it be it is droping it because it can't fit a 4 digit label inside the graphic? I noticed ESRI example doesn't go over 999 either. https://developers.arcgis.com/en/javascript/jssamples/layers_point_clustering.html

Anyone have suggestions on how to get the marker to work for counts of more than 999?

Thanks,
Brian