private static void CreateLine(IEnumerable <MapPoint> points, GraphicsLayer layer, string labelValue)
        {
            var path = new Polyline(points);

            var graphic = new Graphic
            {
                Geometry = path
            };

            graphic.Attributes["LENGTH"] = string.Format("{0}'", labelValue);
            var symbol = new SimpleLineSymbol
            {
                Color = Colors.DarkRed,
                Style = SimpleLineStyle.Solid,
                Width = 2
            };

            graphic.Symbol = symbol;
            graphic.ZIndex = 1000;
            layer.Invoke(l => l.Graphics.Add(graphic));
        }