private void createContainer()
{
   // Get references to required classes:
   // -- m_stationNamesTbl holds a reference to the table with all station names
   // -- m_pipesFC holds a reference to the pipes feature class
   // -- m_containerFC holds a reference to the container feature class
   if (InitClasses() == false)
      return;

   // Start the edit operation.. assumes we're already editing
   m_pEditor.StartOperation();

   // Get a cursor on the station names class and iterate through all stations
   IQueryFilter pStationQF = new QueryFilter();
   ICursor pStationCur = m_stationNamesTbl.Search(pStationQF, true);
   IRow pStationRow = pStationCur.NextRow();
   while (pStationRow != null)
   {
      string stationName = Convert.ToString(pStationRow.get_Value(m_stationNameFI));

      // Get all pipes in the station and return it as a point collection
      IPolyline stationPipes = GetStationPipePolyline(stationName);

      // Create our polygon using the station pipes extent
      ITopologicalOperator4 pTopoOp = (ITopologicalOperator4)stationPipes;
      IPolygon stationBoundary = (IPolygon)pTopoOp.ConvexHull();

      // Create the container feature and assign the extent geometry
      IFeature containerFea = m_containerFC.CreateFeature();
      containerFea.Shape = stationBoundary;
      containerFea.Store();
      pStationRow = pStationCur.NextRow();
   }
   m_pEditor.StopOperation("Create container polygons");
}