// necessary static util functions for stxxl's sorting
 static InternalExtractorEdge min_osm_value()
 {
     return InternalExtractorEdge(MIN_OSM_NODEID,
                                  MIN_OSM_NODEID,
                                  0,
                                  WeightData(),
                                  false, // forward
                                  false, // backward
                                  false, // roundabout
                                  false, // circular
                                  true,  // can be startpoint
                                  TRAVEL_MODE_INACCESSIBLE,
                                  false,
                                  INVALID_LANE_DESCRIPTIONID,
                                  guidance::RoadClassification());
 }
 // necessary static util functions for stxxl's sorting
 static InternalExtractorEdge min_osm_value()
 {
     return InternalExtractorEdge(MIN_OSM_NODEID,
                                  MIN_OSM_NODEID,
                                  0,
                                  WeightData(),
                                  false,
                                  false,
                                  false,
                                  false,
                                  true,
                                  TRAVEL_MODE_INACCESSIBLE,
                                  false,
                                  INVALID_LANE_DESCRIPTIONID,
                                  guidance::RoadClassificationData());
 }
 static InternalExtractorEdge max_osm_value()
 {
     return InternalExtractorEdge(MAX_OSM_NODEID, MAX_OSM_NODEID, 0, WeightData(), false, false,
                                  false, false, true, TRAVEL_MODE_INACCESSIBLE, false,
                                  guidance::RoadClassificationData());
 }