topic Re: Calculate the number of points in a freehand polygon in ArcGIS JavaScript Maps SDK Questions

Calculate the number of points in a freehand polygon

ChristianDebono — Wed, 12 Mar 2014 13:42:12 GMT

I'm drawing a free hand polygon on my map. Now I want to calculate the number of points found in that polygon.

I have done this code, which my now is giving me the number of points found in the map extent rather than the polygon. Now I'm stuck how I'm going to do it since I am new to JavaScript.

function computeZonalStats(evtObj) {
        var geometry = evtObj.geometry;
        map.showZoomSlider();
        map.graphics.clear();

        var symbol = new SimpleFillSymbol("none", new SimpleLineSymbol("dashdot", new Color([255, 0, 0]), 2), new Color([255, 255, 0, 0.25]));
        var graphic = new Graphic(geometry, symbol);

        map.graphics.add(graphic);
        toolbar.deactivate();

        var features = [];
        features.push(graphic);

        var featureSet = new FeatureSet();
        featureSet.features = features;

        var count = 0;
        dojo.forEach(featureLayer.graphics, function (feature) {
                count++;
        });
        alert(count);
    }

Any idea how I could do this please?

Re: Calculate the number of points in a freehand polygon

JakeSkinner — Sun, 12 Dec 2021 07:26:41 GMT

You could do something like this:

array.forEach(map.graphics.graphics, function(feature, index){                            
  if(feature.geometry.type == 'polygon'){
      var count = 0;
      array.forEach(map.graphics.graphics[index].geometry.rings[0], function(ring){
        count++
    })
    
    console.log(count);
    }
})

Re: Calculate the number of points in a freehand polygon

ChristianDebono — Thu, 13 Mar 2014 06:01:55 GMT

Thank you for your reply. The code worked but it is not what I want.

To give you an example I have this map

[ATTACH=CONFIG]32176[/ATTACH]

And I want to calculate the number of points in the polygon drawn. In this case I want to display that 6 points are present in that area.

Re: Calculate the number of points in a freehand polygon

JakeSkinner — Thu, 13 Mar 2014 13:39:37 GMT

Sorry, Christian. I misunderstood you. Take a look at this jsfiddle. I believe this is what you are looking for.

Re: Calculate the number of points in a freehand polygon

ChristianDebono — Thu, 13 Mar 2014 14:02:10 GMT

That's exactly what I need I needed. Thanks a lot for your help.