private void WriteTrackPoint(Waypoint waypoint)
{
xmlWriter.WriteStartElement("trkpt", gpxNamespace);
xmlWriter.WriteAttributeString("lat", XmlConvert.ToString(waypoint.Latitude));
xmlWriter.WriteAttributeString("lon", XmlConvert.ToString(waypoint.Longitude));
xmlWriter.WriteElementString("name", gpxNamespace, waypoint.Name);
xmlWriter.WriteEndElement();
}