Untitled

<html>
<head>
<title>Select features example</title>
<meta http-equiv="X-UA-Compatible" content="chrome=1">
<meta name="viewport" content="initial-scale=1.0, user-scalable=no, width=device-width">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/ol3/3.10.1/ol.css" type="text/css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/ol3/3.10.1/ol-debug.js"></script>
<script src="ol.js"></script>
<script src="jsts_geom_Polygon.js"></script>
<script src="https://cdn.rawgit.com/bjornharrtell/jsts/gh-pages/lib/0.16.0/javascript.util.min.js"></script>
<script src="https://cdn.rawgit.com/bjornharrtell/jsts/gh-pages/lib/0.16.0/jsts.min.js"></script>
<script src="jsts_io_GeoJSONParser.js"></script>
<style>
  html, body {
    padding: 0;
    margin: 0;
  }
  html, body, .map {
    height: 100%;
    width: 100%;
  }
</style>
</head>
<body>
  <div id="map" class="map"></div>
  <button  onclick=withoutaoi();><img src="area.png"></button>

</div>
</div>
<script>

var geojsonFormat = new ol.format.GeoJSON();

var style = new ol.style.Style({
  fill: new ol.style.Fill({
    color: 'rgba(255, 255, 255, 0.3)'
  }),
  stroke: new ol.style.Stroke({
    color: 'rgba(255, 120, 0, 0.6)',
    width: 1
  })
});
var styles = [style];

var highlightStyle = [
  new ol.style.Style({
    fill: new ol.style.Fill({
      color: 'rgba(255, 120, 0, 0.3)'
    }),
    stroke: new ol.style.Stroke({
      color: 'rgba(255, 120, 0, 0.6)',
      width: 1
    })
  })
];

var vector3 = new ol.layer.Vector({
  maxResolution: 0.8,
  source: new ol.source.Vector({
    url: 'ap_taluk.geojson',
   format: new ol.format.GeoJSON({
      defaultDataProjection:'EPSG:4326'
    })
  }),
  style: styles
});


var vector2 = new ol.layer.Vector({
  maxResolution: 0.8,
  source: new ol.source.Vector({
    url: 'flood.geojson',
    format: new ol.format.GeoJSON({
      defaultDataProjection:'EPSG:4326'
    })
  }),
  style: styles
});


var layer1 = new ol.layer.Tile({
            title: 'India',
            source: new ol.source.TileWMS({
              url: '',
              params: {LAYERS: ''}
            }),
            transparent: false
          });
var dist = new ol.layer.Tile({
            title: 'flood',
            source: new ol.source.TileWMS({
              url: '',

              params: {LAYERS: ''}

            })
          });
var distaluk = new ol.layer.Tile({
            title: 'taluk',
            source: new ol.source.TileWMS({
              url: '',

              params: {LAYERS: ''}

            })
          });

 intersectionLayer = new ol.layer.Vector({
  source: new ol.source.Vector()
});

var map = new ol.Map({
  layers: [layer1,vector2,vector3,intersectionLayer,distaluk],
  target: 'map',
  view: new ol.View({
  projection: 'EPSG:4326',
          center: [79.419,15.428],
          zoom: 8

  })
});

var draw_inter = new ol.interaction.Draw({
  type: 'Polygon'
});
map.addInteraction(draw_inter);

draw_inter.on('drawstart', function(evt) {

  intersectionLayer.getSource().clear();
});

var olParser = new jsts.io.olParser();

var geojsonParser = new jsts.io.GeoJSONParser();

draw_inter.on('drawend', function(evt) {
  var poly1 = olParser.read(evt.feature.getGeometry());

  var extent1 = evt.feature.getGeometry().getExtent();

  var source = vector2.getSource();

        var source2 = vector3.getSource();
        //var source4 = vector4.getSource();
        var features = source.getFeatures();
        var features2 = source2.getFeatures();
       // var features4 = source4.getFeatures();

     features.forEach(function(feature) {

            if (!ol.extent.intersects(extent1, feature.getGeometry().getExtent())) {
                          return;
            }
            var poly2 = olParser.read(feature.getGeometry());

            var intersection = poly1.intersection(poly2);
            //alert(intersection);

            intersection = geojsonParser.write(intersection);
            if(intersection.type === 'GeometryCollection' && intersection.geometries.length === 0) {
              return;
            } else {
                intersectionLayer.getSource().addFeature(geojsonFormat.readFeature({
                  type: 'Feature',
                  properties: {},
                  geometry: intersection
                }));
                //alert("flood"+feature.get('geometry'));

            }
  });


  features2.forEach(function(feature) {

            if (!ol.extent.intersects(extent1, feature.getGeometry().getExtent())) {
                          return;
            }
            var poly3 = olParser.read(feature.getGeometry());

            var intersection = poly1.intersection(poly3);
            //alert(intersection);

            intersection = geojsonParser.write(intersection);
            if(intersection.type === 'GeometryCollection' && intersection.geometries.length === 0) {
              return;
            } else {

alert("village"+feature.get('taluk'));
                /*intersectionLayer.getSource().addFeature(geojsonFormat.readFeature({
                  type: 'Feature',
                  properties: {},
                  geometry: intersection
                }));


                /*layersize = intersectionLayer.getSource().getFeatures().length;
alert(" size"+layersize);
 for(i=0;i<layersize;i++){
 alert("village"+feature.get('tehs_name'));
  var count = feature.get('tehs_name');
  alert(count);
  totalarea=0;
  for(j=0;count!==0;j++)
      {
              //alert();
              geoma = intersectionLayer.getSource().getFeatures()[i].getGeometry();
             // alert(geoma);
              coordinates = geoma.getLinearRing(0).getCoordinates();
              alert(coordinates);
              wgs84Sphere = new ol.Sphere(6378137);
              area = Math.abs(wgs84Sphere.geodesicArea(coordinates));
              alert(area);
              totalarea=totalarea+area;
              alert(totalarea)
                //totalarea=totalarea+area;

      }*/
 }
 //alert("village"+feature.get('tehs_name'));

            //}
  });


 layersize = intersectionLayer.getSource().getFeatures().length;
 alert(" village names size"+layersize);
 totalarea=0;
 for(i=0;i<layersize;i++){
    geoma = intersectionLayer.getSource().getFeatures()[i].getGeometry();
    coordinates = geoma.getLinearRing(0).getCoordinates();
    //alert(coordinates)
     wgs84Sphere = new ol.Sphere(6378137);
    area = Math.abs(wgs84Sphere.geodesicArea(coordinates));
    totalarea=totalarea+area;
    //alert("village"+feature.get('tehs_name'));
alert(totalarea);
    }
    if (totalarea > 10000) {
                output = (Math.round(totalarea / 1000000 * 100) / 100) +
                    ' ' + 'km<sup>2</sup>';
          } else {
                output = (Math.round(totalarea * 100) / 100) +
                    ' ' + 'm<sup>2</sup>';
          }
          alert(output);
});

</script>
</body>
</html>