Spatial Connectivity Of Two Air Route Networks In China

Under the influence of aviation demand,the scale of China's air route networks keep expanding,forming a route network system composed of hub airports and non-hub airports.Under the background of civil aviation national strategy,research of airports and route networks become an important aspect in aviation field.About the complicated route networks in China,first,this paper systematically constructs the actual intense-route networks analysis method composed of six indexes,namely,aviation demand degree,spatial connection strength,node degree and degree distribution,average path length index,cluster degree and betweenness centrality.The method changes from simple connectivity index to spatial connectivity index with actual strength.Through the classification of hub airport cities,non-hub airport cities and the classification of short-haul air route,middle-haul air route,long-haul air route,the spatial connectivity of China's air route networks were evaluated by using data of 108 Chinese airport cities and 870 air routes data between airport cities(420 city-to-city air routes and 450 huband-spoke air routes).Secondly,the application results of the actual intense-route networks analysis method are analyzed from the three aspects of saturation state,navigable state and bridge state of route networks.Where,the saturation state is illustrated by aviation demand degree,spatial connection strength.Navigable state is illustrated by node degree and degree distribution,average path length index and cluster degree.The bridge state is illustrated by the degree of betweenness centrality.Finally,typical cases of two air route networks are selected.In city-to-city air route network,this paper selects airport cities with the largest intermediary center,including the hub airport city Beijing and the non-hub airport city Shenzhen.In huband-spoke air route network,this paper also selects airport cities with the largest intermediary center,including the hub airport city Xian and the non-hub airport city Changsha.Through these typical cases,the application result analysis content of the actual intense-route networks analysis method is verified.The results of research show:(1)The spatial connectivity of city-to-city air route network is in a saturated state,especially in the short-haul air route.There is an imbalance between the aviation demand degree and the spatial contact strength between airport cities in hub-and-spoke air route network.The spatial connection is relatively weak and there is room for further expansion.(2)The average path length index of China's overall airline networks is low and the aggregation degree is high,showing the characteristics of small-world network.Hub airport cities have absolute advantages in node degree and average path length,and there are good navigable state with other airport cities.A small number of non-hub airport cities also show the characteristics of high node degree and low average path length index.(3)The matching degree between core airport cities and hub airport cities in city-to-city air route network is relatively high.However,the matching degree between core airport cities and hub airport cities in huband-spoke air route network is weak.Non-hub airports also play an important role in spatial connectivity of air route network.(4)The airport city with the best bridge state in city-to-city air route network is the hub airport city Beijing.As hub airport cities in regions,the airport cities of Kunming and Urumqi also show obvious effects on the bridge state for airport cities in surrounding areas.The airport city with the best bridge state in hub-and-spoke air route network is the hub airport city Xian.Different core cities radiate different areas.By clearly recognizing the spatial connectivity characteristics of the city-to-city air route network and hub-and-spoke air route network,it will help to improve the travel efficiency of passengers.At the same time,it is helpful to make full use of airspace resources to adapt to the change of aviation demand,to serve the evolution of China's passenger air route network and the optimization of air route network structure,and to provide theoretical support for China's air route network layout and selection.