/// <summary>
        /// Raises the element changed event.
        /// </summary>
        /// <param name="e">E event.</param>
        protected override void OnElementChanged(ElementChangedEventArgs<View> e)
        {
            base.OnElementChanged(e);

            if (e.OldElement == null)
            {
                this.mapView = Control as MapView;
                this.mapView.GetMapAsync(this);

                this.myMap = e.NewElement as FieldMap;
            }
        }
        /// <summary>
        /// Get calles when Map is displayed.
        /// </summary>
        /// <param name="e">Event Arguments.</param>
        protected override void OnElementChanged(ElementChangedEventArgs<View> e)
        {
            base.OnElementChanged(e);

            if (e.OldElement == null)
            {
                this.mapView = Control as MKMapView;
                this.mapView.ShowsUserLocation = true;
                this.mapView.DidUpdateUserLocation += this.SetUserPostionOnce;
                this.mapView.AddGestureRecognizer(this.tapGesture);

                /* Readd LFHeatMap project first
                 * Found at https://github.com/TreeWatch/LFHeatMaps
                 * Code:
                 * mapView.RegionChanged += ChangeRegion;
                 */

                this.myMap = e.NewElement as FieldMap;
                this.mapView.OverlayRenderer = this.GetOverlayRender;

                this.AddFields();
            }
        }