With the development of China's economy and the return of Hong Kong and Macao to the motherland, the idea of cooperative developmentof Guangdong, Hong Kong, and Macao around the Bay Area has been put forward by some scholars (Huang, 2008) as early as the beginning of 21st century. At the fifth session of the twelfth National People's Congress held in early 2017, Premier Li Keqiang formally delivered a government work report which stated that“the government will promote closer cooperation between the mainland and Hong Kong and Macao, draw up a plan for the development of the city cluster in the Guangdong-Hong Kong-Macao Greater Bay Area, give full play to the distinctive strengths of Hong Kong and Macao, and elevate their positions and roles in China's economic development and opening-up.” On Jul. 1, 2017, the Framework Agreement on Deepening Guangdong-Hong Kong-Macao Cooperation in the Development of the Greater Bay Area was signed in Hong Kong. Since then, the overall goal of the Bay Area construction has been established, and its key points are to deepen cooperation amongst Guangdong, Hong Kong and Macao, promote the development of the Guangdong-Hong Kong-Macao Greater Bay Area, participate in international cooperation at a high level, enhance the region's leading role in the national economic development and comprehensive opening-up, provide new impetus to the development of Hong Kong and Macao, and maintain long-term prosperity and stability of Hong Kong and Macao.” Also, it was reported that the Strategic Plan for the City Cluster Development of the Guangdong-Hong Kong-Macao Greater Bay Area had beenunder preparation (Dai, 2018) (officially published as the Outline Development Plan for the Guangdong-Hong Kong-Macao Greater Bay Area by the CPC Central Committee and the State Council on Feb. 18, 2019).
The emergence and heated discussion of the concept of the “Bay Area” raises the following questions: firstly, how to understand the spatial organization characteristics of the “Bay Area” and how it differs from ordinary city clusters; secondly, as the name implies, the “Bay Area” has certain natural geographical attribute, that is, the vicinity of coastal ports (Sun, 2017), so does this mean that all city-concentrated areas with this characteristic are possible to be constructed as the “Greater Bay Area?” To address these issues, this paper first analyzes the concept of “Bay Area,” and then takes the Guangdong-Hong Kong-Macao Greater Bay Area as the case to analyze both the static and dynamic spatial characteristics of the city cluster of the Bay Area from perspectives of “space of places” and “space of flows.”Based on these analyses, some thoughts on the planning of the “Greater Bay Area” are proposed.
The analysis scope of this paper includes Guangdong Province, the Hong Kong Special Administrative Region, and the Macao Special Administrative Region. The Guangdong-Hong Kong-Macao Greater Bay Area covers 9 cities, i.e., Guangzhou, Shenzhen, Zhuhai, Foshan, Huizhou, Dongguan, Zhongshan, Jiangmen, and Zhaoqing, plus the two special administrative regions Hong Kong and Macao.①
As an academic research object, “Bay Area” is mostly found in the research literatures of “Bay Area Economy” on New York, San Francisco, Tokyo, and other places in the late 20th century. Relevant domestic research started relatively late and the published outcomesare rare. A unified definition of “Bay Area” has not yet formed among the academia: some scholars believe that the scale of the bay area is close to that of a “metropolitan area” (Li, 2015), while others define its scale as a city cluster (Chen et al., 2010). Some scholar describes it from the perspective of urban relations, considering that it is “an urbanized area consisting of multiple cities and ports orienting towards the same sea area with strong functional collaboration” (Li, 2015); some scholar describes it from a geographical point of view, and considers that “the bay area refers to an area consisting of a bay or a number of connected bays, harbors, and neighboring islands” (Liu,2014); and some scholar defines it from the perspective of an economic zone, believing that the bay area refers to a coastal economic area with the agglomeration force of resources and industries (Li, 2009).
Generally speaking, although city clusters adjacent to a bay are usually described as the necessary physical and geographical attribute of the bay area, it is necessary to emphasize that not all placesthat meet this morphological conditions can be named as bay area. The concept of bay area also has the connotation of economic zone, that is, cities in the region need to be tightly correlated, including spatial mutual dependence andindustrial division of labor as well as cooperation, etc.
In contrast, the Guangdong-Hong Kong-Macao Greater Bay Area, which China is currently making great efforts to build, still has acertain gap with the world’s three major bay areas in terms of overall development level. However, it is already at a world-class level in terms of economic aggregates, and also has certain advantages in terms of port cargo transportation and throughput of airports (see Table 1). Driven by multiple favorable factors such as location condition, population dividend, and the construction of “double innovation” highlands accelerated by supply-side structural reform, the Guangdong-Hong Kong-Macao Greater Bay Area is expected to continuously narrow its gap with the world’s top bay areas and rise to an important growth pole in the Asia-Pacific Region.
Table 1 Comparison of key indicators between Guangdong-Hong Kong-Macao Greater Bay Areaand three major bay areas in the world
Source:Based on data of each area in 2015.
In 1996, the American scholar Manuel Castells published The Rise of the Network Society. It was proposed by Castells that our societies are constructed around flows of capital, flows of information, flows of technology, flows of organizational interactions, flows of images, sounds and symbols.Therefore, the “space of flows” are replacing the “space of places,” traditionally constructed based on the physical contiguity principle, and space becomes the material organization of time-sharing social practices that work through flows (Castells, 1996).
Basically, as two theories of dialectical unity, the “space of places” theory and the “space of flows”theory complement each other statically and dynamically, and together support the theoretical system of modern regional space research. For a long time, urban and regional economics was based on the concept of “space of places.” No matter the classic “central place” theory or “core-periphery” theory, or even the“gravity model” that describes the relationship between towns and cities, they are essentially assimilated to notions of contiguity, i.e., space of places. In recent years, with the improvement of the research framework of city networks, the cognition of urban and regional characteristics from the perspective of space of flows has become a hot topic in empirical research, and considerable progress has been made (Tang and Li, 2014; Zhao, et al., 2014; Cheng and Wang,2017; Cheng et al., 2016).
However, there are limitations in the study of both space of places and space of flows. The former focuses on the scale, structure, and characteristics of the cities or regions themselves from static perspectives, rather than on the relationship between factors; while the space of flows focuses on the dynamic relationship among cities and towns, in which they are often abstracted as spaceless “nodes,”leading to neglect of their inherent attributes.
This research aims to combine the spatial perspectives of “places” and “flows”: when studying the“place” features of the Bay Area, the regional spatial organization from the perspective of urban connectivity is also considered; when studying the relationship among cities and towns from the perspective of “flows,” the characteristics of regional spatial evolution is concerned as well.
From the perspective of “space of places,” this paper first investigates the built-up space of the Guangdong-Hong Kong-Macao Greater Bay Area. Since it is difficult to obtain specific data of construction land at the regional scale, it uses the night-time lights data of the Defense Meteorological Satellite Program (DMSP)in 2003, 2008, and 2013 to approximate the evolution of built-up space in Guangdong-Hong Kong-Macao Greater Bay Area (see Figure 1). It could be seen that, during this period, the Guangdong-Hong Kong-Macao Greater Bay Area showed the characteristics of a concentric ring structure that gradually spread from the core cities of Guangzhou, Buddha, Shenzhen, Dongguan, Hong Kong, and Macao, to the periphery of the Bay Area. And it also shows that during this period, the development of Northern Guangdong② was relatively slow; the Chaoshan region of Eastern Guangdong, where an increased agglomeration effect happened, seemed to have a tendency to gradually develop into a continuous area with the western economic zone of Taiwan Strait; and the Zhanjiang region of the Beibu Gulf also grew to a certain extent – but still has a certain gap compared with the core areas of Guangdong, Hong Kong, and Macao. These characteristics of spatial development have been confirmed by relevant economic and social indicators.
Figure 1 Nighttime light distribution map in Guangdong-HongKong-Macao Greater Bay Area in 2003, 2008, and 2013
Source: Based on thesatellite data of the Defense Meteorological Satellite Program (DMSP) of the USDepartment of Defense.
Enterprises are the directactors of urban economic development, and are directly related to the space of places, the layout of which has a great impact on regional economic development. By analyzing the number of industrial units in the second (December 2008) and the third (December 2013) National Economic Census and their distributions, it can be seen that Guangzhou, Shenzhen, Foshan, Dongguan,Zhongshan, Zhuhai, and other cities have always been the gathering place for enterprises of all sectors in Guangdong Province, which together constitute the core of the Bay Area of the Pearl River Estuary. In 2013, the number of enterprises in the core of the Bay Area accounted for 56.3% of the total numberof Guangdong Province, and accounted for more than 76% of the entire Bay Area,indicating that the development level inside and outside of the Greater BayArea varies greatly.
On the basis of all sectors analysis, excluding general industries such as real estate and water management, and adding upstream industries such as consulting, design, and advertising, the spatial distribution of advanced producer services (APS) is examined. Meanwhile, according to the Industrial Classification for National Economic Activities on the traditional manufacturing industry, high-tech manufacturing industry, cultural industry, and strategic emerging industry, this paper maps out the spatial distribution of enterprises of different sectors (see Figure 2), and further reveals the development characteristics and industrial driving forces of main cities in the core of the Bay Area.
Figure 2 Distribution of different industry units in Guangdong Province in 2013
Source: Based on enterprise data.
In general, although the core of the Bay Area has been the highland for various industries in Guangdong Province, the differentiation among cities in the Bay Area is relatively large and the specialized division of labor is not mature. These differences inindustrial development seem to be caused by different economic growth-drivenmodels: ①As a city with a long-established trade and economy, Guangzhou has a very prominent demand in service industry, cultural industry, etc., and the role of consumption stimulus in the “Three Carriages” is extremely strong. By contrast, the manufacturing industry in Guangzhou is relatively weak. ② Shenzhen and its Bao’an District excel in terms of high-tech manufacturing and strategic emerging industries, which is the fruit of Shenzhen’s development philosophy of vigorous development of knowledge-based industries and economy growth driven by innovation. ③ Dongguan and Foshan are representative cities of traditional manufacturing industries. With their continuous investment drive and the rise of a large number of township andvillage enterprises, they have been acting as the “World Factory” by exportinga large number of manufacturing products over the years. In recent years, taking advantage of its proximity to Shenzhen, Dongguan has shown adual-driving pattern of traditional and emerging industries, with strong momentum in high-tech manufacturing and strategic emerging industries; in contrast, Foshan’s transformation and upgrading is relatively backward, and it is urgent to strengthen high-tech research and the development of manufacturing industry.
The marketization degree of Guangdong, Hong Kong, and Macao is very high, and their system consisting of manufacturing industry and modern service industry is mature. Drawing on the research framework of an interlocking city network proposed by the British geographer Peter Taylor et al. (2001), the paper constructs a regional city network model from the perspective of “space of flows”. The basic approach in this model is to assume that there are relationships between an enterprise headquarters and its branches in terms of production, supply, and sales. Taking Tij as the total number of enterprises with headquarter in city i and branches in city j (weight considered③), and Tji as the total number of enterprises with branches in city i and headquarter in city j, the connectivity between the two cities Vij is the sum of Tij and Tji.
In specific research, it firstly used the industrial unit data of the first, second and third National Economic Census (in December 2004, 2008, and 2013 respectively) to establish anenterprise database, and then screened out all headquarter-branch relationshipsby using SQL statements, from which the enterprise relationship groups at each time point were achieved and the number is around 30,000 – 70,000. During the process, it excludes institutions that are too large in number, too densely distributed, and followed principles of a well-balanced layout (or serviceradius), such as business halls of Unicom, China Mobile, Tietong, etc., and gasstation, bank sub-branch and below (excluding bank branch), and post office, aswell as conducting special check on headquarters of high-level branches of large enterprise in sectors of communication, banking, insurance, oil and petrochemical, etc.④ Secondly, by querying and capturing geographic coordinate data through the network, the geospatial information of headquarter-branch of enterprises was obtained and corrected. And by transforming the internaltwo-mode network of enterprises into network connectivity among cities, it further established the O-D link between district-/county(municipal)-level administrative regions on the GIS platform, and by assigning a T value to each O-D line, the visualization of the city network relationship was finally realized.
Through analyzing the city network index of Guangdong Province over the years, it can be found that the network density was obviously on the rise, which indicates that the connectivity among cities and towns is becoming more and closer and the urban system is becoming mature. As to the network central degree, the city network of Guangdong Province presents a “concentration-expansion” pattern, in which its out-degree centrality showed an obvious increase, indicating its increasingly concentrated regional network control, while the in-degree centrality was declining, indicating a continued expansion of the hinterworlds(see Table 2).
Table 2 Change of the network density and central degree in Guangdong Province from 2004 to 2013⑤
Source: Calculated after converting multivaluedrelationships into binary relationships by Ucinet based on enterprise network data.
From the dynamic changes of regional city network connectivity, the city network connectivity in Guangdong, Hong Kong, and Macao region have shown the following characteristics since 2004.
(1) Guangzhou and Shenzhen: core cities being continuously strengthened
For many years, Guangzhouand Shenzhen have been the two most important cities in Guangdong Province, serving as both regional development hubs and gateway cities to the outside world. During the study period, the connectivity of the two cities increased from 887 to 1,421, and their degree of centrality also increased from 3,088 and 1,733 to 6,142 and 4,281, both ranking the highest in the region.
(2) Guangzhou-Foshan, Shenzhen-Dongguan-Huizhou, and Zhuhai-Zhongshan-Jiangmen: continuously developed core circle of the Bay Area network
The development of the Bay Area’s core circle can be seen more clearly from the three levels of the network (see Figure 3). In 2004, there was Guangzhou-Shenzhou in the first-level urban connectivity map; by 2013, in addition to Guangzhou-Shenzhen, the connectivity between Guangzhou-Foshan (1,000), Shenzhen-Dongguan (785), Guangzhou-Dongguan (635), Guangzhou-Zhongshan, and Shenzhen-Huizhou constituted a close network around the Bay Area. Except for Zhaoqing that was still relatively backward, the eight core cities in the Pearl River Delta (PRD) allhave a high degree of urban centrality and are still in development, which together form the core circle of the Guangdong-Hong Kong-Macao Greater Bay Area in Guangdong Province. At the same time, an industrial network division within the Bay Area has also been formed, such as the traditional manufacturing chain based on Shenzhen-Dongguan-Huizhou and Guangzhou-Foshan, the network highland of high-tech manufacturing in the eastern Bay Area with Shenzhen as the main fulcrum, and the APS and strategic emerging industries networks jointly led by the Bay Area (see Figure 4).
Figure 3 Analysis on the evolution of multi-level city network in Guangdong Province (2004, 2008, and 2013)⑦
Source: Based on enterprise data.
Figure 4 Analysis of enterprise network in Guangdong Province in 2013
Source: Based on enterprise data.
(3) Eastern Guangdong,Western Guangdong, and Northern Mountain Region: peripheral areas affected by the Bay Area
As to the three peripheral areas, i.e., Eastern Guangdong, Western Guangdong, and Northern Mountain Region, it can be clearly observed in the second-level network that the radiation from the core cities of the Bay Area to the regional central citiesin the peripheral areas was increasing, and that the connections between Guangzhou, Shenzhen, and Shantou in the east, Zhanjiang in the west, and Shaoguan in the north were particularly prominent. At the same time, the peripheral regions (Northern Mountain Region, Western Guangdong, Eastern Guangdong, etc.) also showed obvious characteristics of a central place dominated by administrative divisions, which means that there are two different sets of spatial organization logic, i.e., network and central place, behind the current spatial development of Guangdong Province.
According to the division ofthe main functional areas of Guangdong Province, if transforming the regionalcity network from inter-city connection to inter-subregion connection (seeFigure 5), it can be found that the traditional 9 cities of the Pearl River Delta have always been the most economically connected areas within Guangdong Province, the network connectivity of which covered around 70% in the province. And the remaining relatively leading correlations are observed between the Pearl River Delta and the three outer plates, of which the Pearl River Delta related network correlation is above 96%.
Figure 5 Proportion of network connectivity in different regions of Guangdong Province
Source: Based on enterprise data.
Since Hong Kong and Macao are excluded in the National Economic Census, it is difficult to directly measure the network connection between Hong Kong, Macao, and each subregions in Guangdong Province by using the economic census data. However, the basic judgment could be drawn from the flow of various factors that the Bay Area has two major functions: the core of economic development and the hub of spatial organization in the Guangdong-Hong Kong-Macao region, and the Bay Area has the most active economic and social activities, the closest functional connection, and the most perfect network division of labor.
In social network analysis, the whole network is divided into relatively independent “sub-groups” and areas with relatively close network connectivity according to functional correlation. Each sub-groupis called “block.” Using the CONCOR method⑧ provided by Ucinet software, block models of Guangdong Province were constructed to further observe the evolution characteristics of sub-groups in regional city network.
In 2008, Guangdong and Shenzhen could be regarded as two independent sub-groups in the province, showing their core status in the region; while Chaozhou, Shantou, Jieyang, and Shanwei in the eastern area formed a sub-group together with Meizhou, Heyuan, and Huizhou in the eastern part of the Northern Mountain Region; Zhanjiang, Maoming, Yangjiang, Jiangmen, Yunfu, and Zhuhai formed the sub-group of Western Guangdong; and Shaoguan, Qingyuan, Zhaoqing, Foshan, and Zhongshan formed sub-group in the north. In 2013, Guangdong Province experienced a significant spatial restructuring, which somewhat differed from the plate division in the Main Functional Area Planning of Guangdong Province: firstly, led by Guangzhou and Shenzhen, the network cohesion of the core circle including Dongguan, Foshan, Huizhou, and Zhuhai was obviously strengthened, the Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong Plate) has gradually formed, and Shantou, as a regional central city in Eastern Guangdong, was increasingly connected with the Bay Area. Secondly, the sub-groups of Northern and Western Guangdong are nested in each other, in which Zhanjiang, Maoming, Yangjiang, and Jiangmen still constituted an independent sub-group, and Zhaoqing was actually delimitated into the Northern Guangdong sub-group, having a relatively weak network connection with the core of the Bay Area. In general, the Pearl River Delta has experienced increasing economic and social flows and continuous construction of the regional infrastructure network, hence formed a mutual support, which promoted the integration and development of city clusters. In particular, the growing cohesiveness along the Pearl River Estuary has set a good tone for the integrated development of the Guangdong-Hong Kong-Macao Greater Bay Area (see Figure 6).
Figure 6 Spatial substructure change in Guangdong Province based on the analysis of network subgroup in 2008 and 2013
Source: Based on enterprised ata.
On the basis of the above analysis, this paper further discusses the role of core cities in the Greater Bay Area and the functional division in the provincial city network. According to the previous global city rankings by the Globalization and World Cities Research Network (GaWC) (based on global connectivity measurement of modern service industry), in the Guangdong-Hong Kong-Macao Greater Bay Area, Hong Kong has consistently been the highest ranked global city in the Bay Area since 1990s, and has been at the Alpha+ level since 2000 only after the two topglobal cities, London and New York. For a long time, Hong Kong has been leading the entire Guangdong, Hong Kong, Macao Greater Bay Area and even the Pan-Pearl River Delta region to integrate into the world and global economy. In contrast, Macao’s economy, being highly dependent on gaming and tourism, is relatively low in the global city ranking. However, as a world-famous tourist destination, an economic and trade cooperation platform between China and Portuguese-speaking countries, and an exchange and cooperation base for the co-existence of different cultures, it will play an indispensable role in the integrated development of the Bay Area in the future. Besides, the rankings of Guangzhou and Shenzhen rise rapidly in the GaWC’s global cities rankings, becoming major world cities (Alpha, ranking 27) and less major world city (Alpha-, ranking 55) in less than 20 years.
As reflected in the GaWC rankings, the international influence of Guangzhou and Shenzhen have enhanced continuously in recent years, and their global attributes and control over Guangdong, Hong Kong, and Macao Greater Bay Area have also increased. By analyzing the situation of branches set up by enterprises of Guangdong, Shenzhen, Hong Kong, and Macao in other cities in Guangdong Province in 2008 and 2013, their economic impact on Guangdong Province can be measured from aspecific perspective. As it can be seen from the diagram, the number of branches set up by Guangdong and Shenzhen enterprises increased significantly in the provincial scope (see Figure 7), while the branches set up by Hong Kong and Macao enterprises in Guangdong have shrunk to a certain extent (see Figure8).
Figure 7 Analysis of enterprise provincial network of Guangzhou (left) and Shenzhen (right) in 2008 and 2013
Source: Based on enterprise data.
Figure 8 Network analysis of branch institutions set up by Hong Kong (left) and Macao (right) in Guangdong Province in 2008 and 2013
Source: Based on enterprise data.
Diachronically, the current development model of Guangdong, Hong Kong, and Macao has gradually transformed from the original “front shop and back factory” model of Hong Kong and Shenzhen into today’s “Bay Area Integration” model, and the spatial node of the “two sectors,” opening to the outside world and radiating the internal region, has also gradually spread from the gateway cities to the core of entire Bay Area (see Figure 9). Facing the new era, it is of great importance to implement the supply-side structural reform proposed by the central government and build aportal-type, open, and innovation-driven Bay Area to support the constructionof urban city clusters in Guangdong, Hong Kong, and Macao, as well as the long-term development of the Pan-Pearl River Delta region.
Figure 9 Change of development model from the “front shop and back factory” to “Bay Area integration” in Guangdong-Hong Kong-Macao Greater Bay Area
This study indicates that the development situation and characteristics of the Guangdong-Hong Kong-MacaoGreater Bay Area should be analyzed and recognized from the perspectives of“space of places” and “space of flows.” First of all, although Guangdong is usually being regarded as one of the most developed provinces in China, the dual structure between the core and the peripheral areas is still relatively obvious in terms of the provincial development level. After the reform and opening-up, from the first rise of the core area of the Pearl River Delta to the formation of the Guangdong-Hong Kong-Macao Greater Bay Area, spatial contiguity and economic location played a fundamental role. Secondly, the greater development of a region cannot be separated from the smooth and efficient flow of people, capital, information, and products, and it is the “flow” of economic activities in Guangdong, Hong Kong, and Macao that essentially defines the urban system and shapes the Greater Bay Area. The Bay Area surrounding Pearl River Estuary is not only a highland of functional integration, factor mobility, and urban connectivity in the Guangdong-Hong Kong-Macao region, but also has a superior power of network, functioning as acentral hub for the operation of city networks in the peripheral areas. Judging from the current development trend, the Guangdong-Hong Kong-Macao Greater BayArea will further integrate and develop, and the regional function of “two sectors” will be further strengthened. On the one hand, driven by innovation,the Bay Area will be built with a high level of openness to the outside world and will be deeply integrated into the global economy and global city networks.On the other hand, the Bay Area will serve as a hub radiating the externalareas, and lead the coordinated development of Pan-Pearl River Delta by the organization of various flows of factors.
The construction of the Guangdong-Hong Kong-Macao Greater Bay Area has gone through a relatively long period of time from conception and proposal to being put on the agenda. It has the potential to become a “first-class bay area and world-class city cluster,”but the higher level coordinated development of the Bay Area still needs to overcome various invisible obstacles, including system innovation overcoming the institutional differences under the principle of “one country, two systems,” interconnection of infrastructures, cross-regional flow of market factors, coordinated development of industrial systems, sharing and co-construction of major platforms, the integration of living circles, and how to learn from the existing foreign experience, to explore a suitable socialist road for the development of the Greater Bay Area.
It is clear that the integrated development of the Guangdong-Hong Kong-Macao Greater Bay Area has been an objective trend. With the deepening of the urban functional division among Guangzhou, Shenzhen, Hong Kong, and Macao, strengthening contact and cooperation, rather than regional competition, will become the main issue of the Bay Area development. In this context, in accordance with the requirements of the new era, the formulation and implementation of the Bay Area planning will be the priority for the future development of Guangdong, Hong Kong, and Macao city-region, which needs to respond to important concerns of China’s opening-up strategy and the Belt and Road Initiative construction, and put forward the role and objective of the Bay Area in the global city network. At the same time, the role of labor division that city clusters in the Bay Area play in the national urban system and city network should be clarified from the perspective of driving the Pan-Pearl River Delta region. Also, under the guidance of the regional policy framework, and in the light of the strategic layout of the entire Bay Area and the role of cities it involves, it is necessary to carry out stock-based integration and make incremental construction plans for transportation, information, service, and other facilities, in order to realize mutual support and the promotion of the facility network and the urban functional network.
Finally, it is noteworthy that, considering the specificity of the Greater Bay Area development in the world and in China, the planning and construction is extremely challenging, which should only follow the trend rather than being forced.
From Urban Planning Forum, 2018, (4), pp. 24 – 33.
① Due to data availability, Hong Kong and Macao are not covered in some analyses.
②According to the Major Function Zone Planning of Guangdong Province, theprovince is divided into Pearl River Delta Region (including 9 cities, i.e.,Guangzhou, Shenzhen, Zhuhai, Foshan, Jiangmen, Dongguan, Zhongshan, Huizhou, Zhaoqing), Eastern Guangdong Region (including 4 cities, i.e., Shantou, Chaozhou, Jieyang, and Shanwei), Northern Mountain Region (including 5 cities, i.e., Shaoguan, Heyuan, Meizhou, Qingyuan, Yunfu) and Western Guangdong Region (including 3 cities, i.e., Zhanjiang, Maoming, and Yangjiang).
③ In this study, the weight of branch institution above the sub-branch level is assigned 1, and the weight of sub-branch institution is assigned 0.5.
④ For example, without the specific correction, the superior headquarter of Industrial and Commercial Bank of China Ltd. Huzhou Branch will be identified as Industrial and Commercial Bank of China Ltd. While actually, enterprise structure of this kind shows obvious administrative hierarchy characteristics and the superior headquarter should be corrected as Industrial and Commercial Bank of China Zhejiang Branch. The other large enterprises in this analysis are corrected specifically as well.
⑤ Network density is used to indicate the connection degree of nodes in the network, and the higher the density value is, the closer the city’ functional connection is.The formula is:
Where D means the citydensity network, K is the number of nodes, and T(i, j) and j are the connection quantities between i and j. The central potential refers to the overall centrality of the network, and the value of which is assigned between 0 – 1.The lower the value is, the more evenly distributed the network is; while thevalue close to 1 indicates the centralization of power in the network and the imbalance of the network structure. According to the distribution of regional network power and network hinterland, the central potential can also be divided into out-degree central potential and in-degree central potential. The calculation formula is:
In which, Ci is the degree of centrality of a city in a network, the value of which can be used to measurethe city’s influence and control over other cities. For a directed city network, a node has two centrality indexes, i.e., degree of inward centrality (in-degree in short, Ii) and degree of outward centrality (out-degree in short, Oi) , and the sum of them is the degree of centrality of the node.
⑥This paper takes 5%, 15%, 25%, and 50% of the maximum value of the city network connectivity in 2013 as the break points, and divides the network connectivity intensity into strong connectivity, medium-strong connectivity, medium connectivity, medium-weak connectivity, and weak connectivity (same hereinafter).
⑦The three levels in the figure correspond to a connectivity of more than 25% , 5%–25%, and less than 5% , respectively.
⑧The CONCOR method is an iterative correlation convergence method, which determines whether each “position” is 0-block or 1-block with reference to the average density of the whole network, where 0-block represents no relationship and 1-block represents a relationship. Based on this, the clustering of each network member can be calculated accordingly.
⑨From the Framework Agreement on Deepening Guangdong-Hong Kong-Macao Cooperation in the Development of the Greater Bay Area.
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Zhang Yishuai, PhD Candidate, College of Architecture and Urban Planning, Tongji University, Shanghai, P. R. China.
Zhao Min (corresponding author), Professor, Doctoral Supervisor, College of Architecture and Urban Planning, Tongji University, Shanghai, P. R. China.
Wang Qixuan, Postgraduate Candidate, College of Architecture and Urban Planning, Tongji University, Shanghai, P. R. China.
Cheng Yao, Assistant Professor, College of Architecture and Urban Planning, Tongji University, Shanghai, P. R. China.