// ==================================================
        // Methods

        public void SetVersion(GpxSchemaVersion version)
        {
            if (_xml != null)
            {
                throw new Exception("Header already written.");
            }
            else
            {
                Version = version;
            }
        }
 private void InitXml()
 {
     // check for file version
     _ns = new XmlNamespaceManager(_xml.NameTable);
     if (_xml.DocumentElement.FirstChild.Name == "metadata")
     {
         _version = GpxSchemaVersion.Version1_1;
         _ns.AddNamespace("gpx", OrthoConstants.GpxNamespaceV1_1);
     }
     else
     {
         _version = GpxSchemaVersion.Version1;
         _ns.AddNamespace("gpx", OrthoConstants.GpxNamespaceV1);
     }
 }