remove prev layes

catalog/static/js/openLayers4.js

@@ -94,7 +94,7 @@ OpenStreetMapsClass.prototype.addPolygon = function(coords)
 		polyCoords.push(ol.proj.fromLonLat([parseFloat(c[0]), parseFloat(c[1])], 'EPSG:3857', 'EPSG:4326'));
 	}
 
-	//todo: remove older features in map, if there is a feature
+	// remove previous layers
 	this.vectorLayer.getSource().clear();
 
 	// create feature

catalog/static/js/sidtMap.js

@@ -89,10 +89,16 @@ function sidtMap(divID, lng, lat, z)
 	var self = this;
 	this.features = new ol.Collection();
 	this.interaction = new ol.interaction.Draw({features: this.features,type: "Polygon"});
-	this.tempFeature = null;
 
-	var style = new ol.style.Style({stroke: new ol.style.Stroke({color: 'rgba(0,0,100,0.8)', width: 2}),
-					 fill: new ol.style.Fill({ color: 'rgba(0,100,200,0.5)'}) });
+	var style = new ol.style.Style({
+		stroke: new ol.style.Stroke({
+			color: 'rgba(0,0,100,0.8)', 
+			width: 2
+		}),
+		fill: new ol.style.Fill({ 
+			color: 'rgba(0,100,200,0.5)'
+		}) 
+	});
 
 	this.map.on("moveend",function(e){self.onMapMove(e)});
 	this.map.on("pointerdrag",function(e){self.onDrag(e)});
@@ -104,27 +110,22 @@ sidtMap.prototype = Object.create( OpenStreetMapsClass.prototype );
 sidtMap.prototype.addInteraction = function()
 {
 	var self = this;
-	this.interaction = new ol.interaction.Draw({
-	  source:this.vectorLayer.getSource(),
-          features: this.features,
-          type: "Polygon"
 
-        });
+	this.interaction = new ol.interaction.Draw({
+		source:this.vectorLayer.getSource(),
+		features: this.features,
+		type: "Polygon"
+	});
+	
 	this.interaction.on("drawend",function(e){
-						document.getElementById("id_polygon").value =e.feature.getGeometry().clone().transform( 'EPSG:3857', 'EPSG:4326').getCoordinates();
-						
-						self.tempFeature=e.feature;
-						}
-			);
+		document.getElementById("id_polygon").value =e.feature.getGeometry().clone().transform( 'EPSG:3857', 'EPSG:4326').getCoordinates();					
+	});
+	
 	this.interaction.on("drawstart",function(e){
-							if(self.tempFeature!=null)
-							{
-						  		self.vectorLayer.getSource().removeFeature(self.tempFeature);
-							}
-						}            
+		self.vectorLayer.getSource().clear();
+	});
 
-			);
-        this.map.addInteraction(this.interaction);
+	this.map.addInteraction(this.interaction);
 }
 //------------------------------------------------------------------------------
 sidtMap.prototype.onMousemove = function(e)