private void WpfMap_Loaded(object sender, RoutedEventArgs e)
        {
            wpfMap1.MapUnit = GeographyUnit.DecimalDegree;


            InMemoryFeatureLayer inmLayerWith5000Features = new InMemoryFeatureLayer();
            inmLayerWith5000Features.Open();
            inmLayerWith5000Features.Columns.Add(new FeatureSourceColumn("id"));
            inmLayerWith5000Features.Close();
            inmLayerWith5000Features.ZoomLevelSet.ZoomLevel01.DefaultPointStyle = PointStyles.Capital1;
            inmLayerWith5000Features.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
            inmLayerWith5000Features.ZoomLevelSet.ZoomLevel01.DefaultTextStyle = TextStyles.Antarctical("id");

            InMemoryFeatureLayer inmLayerWith12500Features = new InMemoryFeatureLayer();
            inmLayerWith12500Features.Open();
            inmLayerWith12500Features.Columns.Add(new FeatureSourceColumn("id"));
            inmLayerWith12500Features.Close();
            inmLayerWith12500Features.ZoomLevelSet.ZoomLevel01.DefaultPointStyle = PointStyles.Capital1;
            inmLayerWith12500Features.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
            inmLayerWith12500Features.ZoomLevelSet.ZoomLevel01.DefaultTextStyle = TextStyles.Antarctical("id");


            InMemoryFeatureLayer inmLayerWith50000Features = new InMemoryFeatureLayer();
            inmLayerWith50000Features.Open();
            inmLayerWith50000Features.Columns.Add(new FeatureSourceColumn("id"));
            inmLayerWith50000Features.Close();
            inmLayerWith50000Features.ZoomLevelSet.ZoomLevel01.DefaultPointStyle = PointStyles.Capital1;
            inmLayerWith50000Features.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
            inmLayerWith50000Features.ZoomLevelSet.ZoomLevel01.DefaultTextStyle = TextStyles.Antarctical("id");


            Random random = new Random();
            for (int i = 0; i < 5000; i++)
            {
                Feature feature = new Feature(random.Next(-180, 180), random.Next(-90, 90));
                feature.ColumnValues.Add("id", "the " + i.ToString() + " feature in inmLayerWith5000Features");
                inmLayerWith5000Features.InternalFeatures.Add(feature);
            }


            for (int i = 0; i < 12500; i++)
            {
                Feature feature = new Feature(random.Next(-180, 180), random.Next(-90, 90));
                feature.ColumnValues.Add("id", "the " + i.ToString() + " feature in inmLayerWith5000Features");
                inmLayerWith12500Features.InternalFeatures.Add(feature);
            }


            for (int i = 0; i < 50000; i++)
            {
                Feature feature = new Feature(random.Next(-180, 180), random.Next(-90, 90));
                feature.ColumnValues.Add("id", "the " + i.ToString() + " feature in inmLayerWith5000Features");
                inmLayerWith50000Features.InternalFeatures.Add(feature);
            }

            LayerOverlay ov1 = new LayerOverlay();
            ov1.Layers.Add(inmLayerWith5000Features);
            ov1.Layers.Add(inmLayerWith12500Features);
            ov1.Layers.Add(inmLayerWith50000Features);

            InMemoryFeatureLayer inmLayerWith5Features = new InMemoryFeatureLayer();
            inmLayerWith5Features.Open();
            inmLayerWith5Features.Columns.Add(new FeatureSourceColumn("id"));
            inmLayerWith5Features.Close();
            inmLayerWith5Features.ZoomLevelSet.ZoomLevel01.DefaultPointStyle = PointStyles.Capital1;
            inmLayerWith5Features.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
            inmLayerWith5Features.ZoomLevelSet.ZoomLevel01.DefaultTextStyle = TextStyles.Antarctical("id");

            InMemoryFeatureLayer inmLayerWith2000Features = new InMemoryFeatureLayer();
            inmLayerWith2000Features.Open();
            inmLayerWith2000Features.Columns.Add(new FeatureSourceColumn("id"));
            inmLayerWith2000Features.Close();

            inmLayerWith2000Features.ZoomLevelSet.ZoomLevel01.DefaultPointStyle = PointStyles.Capital1;
            inmLayerWith2000Features.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
            inmLayerWith2000Features.ZoomLevelSet.ZoomLevel01.DefaultTextStyle = TextStyles.Antarctical("id");


            for (int i = 0; i < 5; i++)
            {
                Feature feature = new Feature(random.Next(-180, 180), random.Next(-90, 90));
                feature.ColumnValues.Add("id", "the " + i.ToString() + " feature in inmLayerWith5000Features");
                inmLayerWith5Features.InternalFeatures.Add(feature);
            }


            for (int i = 0; i < 2000; i++)
            {
                Feature feature = new Feature(random.Next(-180, 180), random.Next(-90, 90));
                feature.ColumnValues.Add("id", "the " + i.ToString() + " feature in inmLayerWith5000Features");
                inmLayerWith2000Features.InternalFeatures.Add(feature);
            }

            LayerOverlay ov2 = new LayerOverlay();
            ov2.Layers.Add(inmLayerWith5Features);
            ov2.Layers.Add(inmLayerWith2000Features);


            wpfMap1.Overlays.Add(ov1);
            wpfMap1.Overlays.Add(ov2);

            ov1.Drawing += new EventHandler<DrawingOverlayEventArgs>(ov1_Drawing);
            ov1.Drawn += new EventHandler<DrawnOverlayEventArgs>(ov1_Drawn);
            ov2.Drawing += new EventHandler<DrawingOverlayEventArgs>(ov2_Drawing);
            ov2.Drawn += new EventHandler<DrawnOverlayEventArgs>(ov2_Drawn);

            wpfMap1.CurrentExtent = new RectangleShape(-180, 90, 180, -90);
            wpfMap1.Refresh();
        }

        void ov2_Drawn(object sender, DrawnOverlayEventArgs e)
        {
            System.Diagnostics.Debug.WriteLine("ov1 STOP Time:" + stopwatch.Elapsed.TotalMilliseconds);
        }

        void ov2_Drawing(object sender, DrawingOverlayEventArgs e)
        {
            if (!stopwatch.IsRunning)
            {
                stopwatch.Start();
            }
        }

        Stopwatch stopwatch = new Stopwatch();

        void ov1_Drawn(object sender, DrawnOverlayEventArgs e)
        {
            System.Diagnostics.Debug.WriteLine("ov2 STOP Time:" + stopwatch.Elapsed.TotalMilliseconds);

        }
        void ov1_Drawing(object sender, DrawingOverlayEventArgs e)
        {
            if (!stopwatch.IsRunning)
            {
                stopwatch.Start();
            }

        }