private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            InMemoryFeatureLayer inmemoryLayer = new InMemoryFeatureLayer();
            inmemoryLayer.ZoomLevelSet.ZoomLevel01.DefaultPointStyle = PointStyles.City3;
            inmemoryLayer.ZoomLevelSet.ZoomLevel01.DefaultAreaStyle = AreaStyles.Forest1;
            inmemoryLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
            inmemoryLayer.InternalFeatures.Add(new Feature(poupPoint));
            LayerOverlay overlay = new LayerOverlay();
            overlay.Layers.Add(inmemoryLayer);
            Map1.Overlays.Add("inMemoryOverlay", overlay);

            PopupOverlay popUpOverlay = new PopupOverlay();
            Map1.Overlays.Add("popUpOverlay", popUpOverlay);
          Map1.MouseMove+=new MouseEventHandler(Map1_MouseMove);
            
        }

        PointShape poupPoint = new PointShape(0, 0);

        void Map1_MouseMove(object sender, MouseEventArgs e)
        {
            Point screenCoordinate = e.GetPosition(Map1);
            PointShape point = Map1.ToWorldCoordinate(screenCoordinate);
            
            PopupOverlay popupOverlay = Map1.Overlays["popUpOverlay"] as PopupOverlay;
            if (point.X < 180 && point.X > -180 && point.Y < 90 && point.Y > -90)
            {
                if (DecimalDegreesHelper.GetDistanceFromDecimalDegrees(point, poupPoint, DistanceUnit.Kilometer) < 1000)
                {
                    if (popupOverlay.Popups.Count < 1)
                    {
                        Popup popUp = new Popup(poupPoint);
                        popUp.Content = "x:0 y:0";
                        popupOverlay.Popups.Add(popUp);
                        Map1.Refresh(popupOverlay);
                    }
                }
                else
                {
                    popupOverlay.Popups.Clear();
                    Map1.Refresh();
                }
            }
        }