ArcGISWindowsPhoneSDK.AddGraphics.AddPictureMarkerAndTextGraphics C# (CSharp) Method

        private void AddPictureMarkerAndTextGraphics()
        {
            string gpsNMEASentences = "$GPGGA, 92204.9, -35.6334, N, -60.2343, W, 1, 04, 2.4, 25.7, M,,,,*75\r\n" +
                                     "$GPGGA, 92510.5, -49.9334, N, -65.2131, W, 1, 04, 2.6, 1.7, M,,,,*75\r\n";
            string[] gpsNMEASentenceArray = gpsNMEASentences.Split('\n');

            GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;

            for (int i = 0; i < gpsNMEASentenceArray.Length - 1; i++)
            {
                string[] gpsNMEASentence = gpsNMEASentenceArray[i].Split(',');
                MapPoint mp = new MapPoint(Convert.ToDouble(gpsNMEASentence[4]), Convert.ToDouble(gpsNMEASentence[2]));
                MapPoint conv_mp = wm.FromGeographic(mp) as MapPoint;

                Graphic graphic = new Graphic()
                {
                    Geometry = conv_mp,
                    Symbol = GlobePictureSymbol
                };

                graphicsLayer.Graphics.Add(graphic);

                TextSymbol textSymbol = new TextSymbol()
                {
                    FontFamily = new System.Windows.Media.FontFamily("Arial"),
                    Foreground = new System.Windows.Media.SolidColorBrush(Colors.Black),
                    FontSize = 18,
                    Text = gpsNMEASentence[9]
                };

                Graphic graphicText = new Graphic()
                {
                    Geometry = conv_mp,
                    Symbol = textSymbol
                };

                graphicsLayer.Graphics.Add(graphicText);
            }
        }