public Node Add(Node e)
        {
            _entities.Nodes.AddObject(e);

            return e;
        }
 public Node Update(Node e)
 {
     throw new NotImplementedException();
 }
        private void ReadNode()
        {
            Node node = new Node();

            node.Id = Convert.ToInt64(_reader.GetAttribute("id"));
            node.Lat = String2Coordinate(_reader.GetAttribute("lat"));
            node.Lon = String2Coordinate(_reader.GetAttribute("lon"));

            _reader.ReadStartElement(); // node
            _reader.Skip();
            _numberNodes++;

            while (_reader.Name == "tag")
            {
                _reader.ReadStartElement();
                _reader.Skip();
            }

            if (_reader.NodeType == XmlNodeType.EndElement)
                _reader.ReadEndElement(); // node

            _nodes.Add(node.Id,node);
        }