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Research on urban spatial networks based on "flow" data has become a new paradigm in the assessment of urban spatial connections and the delineation of metropolitan influence areas in urban geography and territorial spatial planning. Research on urban connections in Chongqing focuses primarily on districts and counties within the city's administrative region, utilizing passenger or cargo flow data to study the spatial structure of the network within Chongqing. However, few studies have been conducted on cross-provincial administrative regions between Chongqing and its neighboring areas, which does not align with the actual influence of Chongqing's metropolitan area. Based on highway traffic passenger flow data, this study employs social network and GIS spatial analysis methods to study the urban network spatial structure between Chongqing and its neighboring areas from the perspective of passenger flow connections. The results indicate the following: (1) Chongqing's central urban area serves as the absolute core of the urban network, with Changshou, Jiangjin, and Bishan as important nodal cities. Fuling, Bishan, and Changshou exhibit notable accessibility within the network, while Fuling, Qianjiang, Jiangjin, and Wanzhou play prominent intermediary roles. There are no prominent regional nodes outside Chongqing's administrative area, and the growth poles for the development of the Chengdu-Chongqing Economic Circle need further cultivation. (2) The passenger flow network between Chongqing and its neighboring areas exhibits a three-tiered axial connection, with the overall network displaying a distinct radial characteristic. The urban clusters in northeastern Chongqing form a distinct band-shaped axis along the Yangtze River with Chongqing. The urban clusters in southeast Chongqing and their neighboring areas exhibit radial axes, with relatively weak connections to the central urban area. Some areas in Guang'an and Dazhou have overcome provincial administrative boundaries, and the network hierarchy is distributed according to "4(level 1)+15(level 2)+18(level 3)." (3) The cohesive subgroups between Chongqing and its neighboring areas demonstrate a high degree of geographical proximity, forming a "core-periphery" structure. This reflects the significant influence that factors such as spatial distance and road extensions exercise on the road passenger transport network. Conducting research on the spatial structure of cross-administrative urban networks from the perspective of highway passenger flow holds significant theoretical and practical value for enriching research on the spatial structure of cross-administrative metropolitan areas and promoting the linkage between Chongqing's metropolitan area and its surrounding regions.

The shift of the global shipping network center to East Asia is a trend that has been widely recognized. As the main carrier of logistics and trade transportation in the RCEP and the surrounding areas of the South China Sea, research on the container port system and network structure in the surrounding areas is of great significance for understanding the characteristics and optimization of maritime trade channels in the surrounding countries and regions of the South China Sea. Based on route data from the world's top eight shipping companies, we selected 37 container ports around the South China Sea as the research objects of this study. First, we constructed a two-way network on their existing route distribution and studied their port system characteristics and network structure using complex network centrality indicators and network structure models, such as degree centrality, proximity centrality, intermediate centrality, and right index. The conclusions are as follows: (1) In recent years, the status of container ports in countries and regions along the South China Sea within the world container port system has generally been on the rise. The overall ranking of port throughput is relatively stable. The capacity of container ports in seven countries around the South China Sea is unevenly distributed, mainly in China and Singapore. (2) In terms of network centrality analysis, port routes, such as Shenzhen, Singapore, Hong Kong, Kaohsiung, Qingdao, and Shanghai, are abundant, and there are many regions that can conduct trade directly, which are less affected by other port connections. Shanghai, Shenzhen, Ningbo, Zhoushan, Guangzhou, and other ports play an important role as tandem intermediaries in international container routes and have a strong ability to control the shipping network. (3) In terms of network level, the port network status is divided into four levels according to the differentiation of port throughput scale and center degree. The first-tier ports are the home ports of international routes, including Shanghai, Singapore, Shenzhen, Ningbo Zhoushan, Guangzhou, Qingdao, and Hong Kong. Ports on the second layer are the hub ports of international routes, including Kaohsiung, Tanjung Pelepas, Xiamen, Tianjin, Laem Chabang, Klang, and Ho Chi Minh. This layer contains mostly the hub ports of international routes, with a good degree of central development. Ports on the third layer are the international route connecting ports, including Haiphong, Qinzhou, Dalian, Tanjung Priok, Manila, Tanjung Perak, Lianyungang, Cai Mep, Yantai, Yingkou, Rizhao, and Fuzhou. The relative centrality of ports on this layer is low, and the throughput is relatively limited. Layer four ports are regional feeder ports, including Jinzhou, Taicang, Taichung, Dongguan, Tangshan, Nanjing, Quanzhou, Nantong, Zhuhai, Jiaxing, and Haikou, which have become popular transshipment ports owing to their geographical characteristics. (4) In terms of network structure, the overall network can be divided into four port communities. Among them, community one has a clear central attribute, to which community two is closely connected, and community three is fed to the port group. Community four has clear small world attributes, and the port routes within this group are relatively independent.

The proposal of a national strategy for the "New Western Land Sea Corridor" will affect the reconstruction of the overall freight distribution pattern in western China. As the most important hub node for cargo distribution and transshipment in inland areas, the inland port (or dry port) is of great significance to regional economic development, logistics systems, and the construction of a new regional development pattern. Therefore, 111 papers on inland port research in international core journals have been selected in this study to systematically review the research status of inland ports and put forward the key directions and development trends for future research to serve the theoretical research and construction planning practice of inland ports in China, and globally. In this study, the literature metrology method is adopted to divide inland port research and development into three stages: the first stage is the initial stage (before 2005); the second stage is the slow fluctuating growth stage (2006-2017); the third stage is the rapid increase stage (2018-present). Scholars are interested in inland port research mainly from mainland China, the Netherlands, Hong Kong, the United Kingdom, the United States, and other countries (regions). Related research topics on inland ports are mostly combined with transportation, logistics, and other fields, which indicates that inland ports have become an important part of transportation systems and supply chain transportation networks. Among specific related research topics, the concept of inland ports is an important research topic, mainly focusing on the differences in naming and function, facilities of inland ports under different geographical backgrounds, and additional functions extended with economic development; however, its concept has not yet been unified. Research on the spatial layout system of inland ports shows that the inland port site selection and layout can be roughly summed up as a supply chain-oriented pattern, and industrial cluster-oriented pattern; the former often near port cargo distribution of traffic nodes, while the latter is on the border between the end of the supply chain. The location and layout of inland ports are influenced by economic foundation, transportation infrastructure, and local policy factors. Inland ports have a profound impact on the region. In terms of spatial effects, they have an impact on urban spatial planning and land use; in terms of economic effects, they can promote regional economic development and employment; in terms of environmental effects, they can reduce energy consumption and emissions, and promote the realization of regional sustainable development. In the operation and control of inland ports, special attention should be paid to the relationship between port planning and each manager, as well as to the management system, to realize the efficient, sustainable, and healthy development of inland ports. Finally, based on the new trends of global inland port logistics research and the realistic demand of China, we put forward several suggestions for future research, including the redefinition of dry ports, spatial layout and planning of inland ports, their regional influence, the port-city relationship, risk of investment, and potential benefits of inland ports.

As an emerging strategic industry with high added value, wide application, and low energy consumption, the software and information technology service industry plays an important role in promoting the development and transformation of the national economy. The reasonable layout of the software and information technology service industry is of great significance to issues such as industrial development and optimizing the urban spatial structure. Based on the registration data of industrial and commercial enterprises, this study uses spatial analysis methods, such as Kernel Density(KDE) and Multi-Distance Spatial Cluster Analysis(Ripley's K), to study the spatial pattern evolution characteristics of software and information technology service enterprises in the main urban area of Chongqing from 2002 to 2017. In addition, this paper uses the Tobit model to explore the impact of location , transportation, industrial agglomeration and policies on the location of enterprises. The research shows that: (1) From the current distribution, the urban middle circle, which is 4-12 km away from the city center, has become the main space for the distribution of software and information technology service enterprises in the main urban area; it forms a "double peak" circle distribution. The spatial distribution pattern is expressed as "one main twice," and the agglomeration feature is remarkable. (2) From 2002 to 2017, while the distribution of enterprises was suburbanized, a large number of enterprises were concentrated 6-8 km away from the city center. The circle distribution changed from a "double peak" structure to a "single peak" structure, and the spatial pattern gradually evolved from a single center to "one main twice"; further, the intensity and scale of agglomeration also increased continuously. (3) Industrial agglomeration has the most significant impact on the location selection of software and information technology service enterprises in the main urban area. The location conditions and intra-city traffic factors have significant impact. The factors of spatial planning policy and external transportation facilities on the selection of enterprises' location are not significant. These research results show that the spatial distribution of the software and information technology service industry in the main urban area of Chongqing presents the characteristics of being concentrated in the middle layer of the city, having multiple centers, and of suburbanization. Compared to software companies in Shanghai, Nanjing, and other cities, the special landscape pattern and relatively backward development stage make the software and information technology service companies in the main urban area of Chongqing have a stronger preference for the urban middle circle. Additionally, the results of the influencing factors of location choice indicate that with the deepening of industry development, the role of various factors in the choice of enterprises' location is also changing. For Chongqing, which is undergoing industrial upgrading, these research findings can provide reference and guidance for the upgrading and transformation of Chongqing's industrial structure, and also provide a basis for understanding the optimization of the urban spatial structure of the main urban area. Nevertheless, due to problems such as data acquisition and the difficulty of quantifying some corporate location factors, this research is possibly inadequate and more in-depth research is needed.

Population flow is an important component of regional spatial network, but there are few empirical studies on its quantity and spatial pattern in outflow areas in extant literature. The development of the population flow pattern since 2010 has important theoretical contributions to the understanding of the population flow pattern and mechanism in modern China. Based on the Migrants Dynamic Survey of China's floating population by the National Health Commission, PRC, in 2017, this study systematically analyzed the spatial pattern and mobile network of the floating population in Sichuan-Chongqing, one of the most important outflow areas in China. The study found that the scale of the interregional outflow in this area is still large in terms of floating population. However, there has been a certain degree of population backflow since 2010 and the floating population has begun to surpass interregional mobility, which shows that Sichuan-Chongqing is increasingly attracting population. In terms of the spatial distribution pattern of floating population, the outflow to other provinces is mainly from the county units in the northeastern part of Sichuan-Chongqing and the inflow is mainly from the neighboring provinces of Sichuan-Chongqing. Further, the outflow to urban agglomerations is mainly toward the eastern coastal regions and the neighboring provinces in southwest China, whereas the inflow is toward the urban areas of Chengdu and Chongqing. Overall, the population flow here is mainly toward the urban center in both Chengdu and Chongqing. The areas that attract the utmost population flow are as follows, in order: the urban area of Chongqing; the urban area of Chengdu, which is a center for Sichuan; and the urban areas of Panzhihua and Yibin. The distribution of the population flow is highly concentrated in the central region of Sichuan-Chongqing, which shows a spatial pattern of "core-periphery." Short-distance population flow dominates the mobility network in this region. Further, the core of Chongqing urban area is closely connected with not only most districts and counties in the city but also Guang'an City and Nanchong City, Sichuan Province, whereas the core of Chengdu urban area is closely connected with the Chengdu Plain Economic Zone. Cities located along the border of Sichuan and Chongqing, such as Zigong, Yibin, Ziyang, Neijiang, and Dazhou, are greatly influenced by the cores of both Chengdu and Chongqing, and the population flow network is comparatively complex. The population flow between the two cores is weak. This shows that the administrative boundary between Chongqing and Sichuan has a significant influence on the population flow in this area.

As one of the important factors affecting regional economic development, expressway construction has been a concern of scholars worldwide. China's highway construction is relatively late compared with Western developed countries, but the speed is faster. The construction is in step with China's high-speed economic growth stage. However, there is temporal and spatial heterogeneity in expressway construction and economic development across different regions of the world, which has not been fully documented in the current literature. Using panel data from 1999 to 2019 encompassing expressway construction and regional economic development indicators of 233 prefecture-level cities in China, this paper delves into the dynamics of expressway infrastructure development and its correlation with regional economic growth. Using regression analysis, the study provides the following key insights: (1) As of 2019, expressway density exhibits a spatial pattern characterized by a higher density in major urban clusters and provincial capitals and a lower density in northeastern China and border regions. Between 1999 and 2009, the eastern region witnessed the fastest increase in expressway density, while the central region surpassed the eastern region in density growth during 2009–2019. Over the past two decades, there has been a significant overall increase in expressway growth nationwide, with the distribution of prefecture-level cities experiencing relatively faster growth rates aligning with the principles of the "National Highway Network Planning". (2) Although there has been an overall increase in per capita GDP among prefecture-level cities, there has also been a widening disparity between these cities. Meanwhile, the total GDP of the central and western regions has experienced notable growth, effectively closing the gap with the eastern region. While total GDP demonstrates balanced development, per capita GDP displays a more varied pattern of growth. (3) Expressway density has played a positive role in fostering regional economic growth across the country over the long term. However, its impact has been more pronounced in the western region from 1999 to 2009 and increasingly significant in the eastern and central regions from 2009 to 2019. [ABSTRACT FROM AUTHOR]

This paper focuses on the level of urban–rural integration development and its spatio–temporal evolution patterns in the Chengdu-Chongqing Economic Circle. It constructs an evaluation indicator system encompassing five dimensions: population, economy, society, ecology, and space. By comprehensively using statistical data and multi-source spatio–temporal data and employing methods such as the entropy method, ESDA, obstacle degree model, and various statistical techniques, the study measures and analyzes the level of urban–rural integration development at three time points: 2010, 2015, and 2020. The findings are as follows: (1) The overall level of urban–rural integration is low, predominantly at low to lower-middle levels, with a clear core-periphery spatial pattern where central urban areas such as Chengdu's central seven districts and Chongqing's central urban districts are high-value cores, whereas peripheral and central regional areas are less integrated. (2) From 2010 to 2020, there was a steady increase in integration levels, transitioning from a single-core to a more dynamic point-axis structure with emerging regional growth poles. However, this transition was accompanied by reduced inequality of urban–rural integration within each city, while disparities among central urban areas within its cities gradually increased. (3) The analysis of obstacles across dimensions indicates that spatial integration faces the most significant barriers, mainly due to geographical conditions and development constraints in southwestern mountainous counties. In contrast, barriers to economic and social integration, though initially lower, have gradually increased, highlighting imbalances between economic growth and social service provision. Overall, this study not only provides a systematic measurement and analytical framework for the integration and development of urban and rural areas in the Chengdu-Chongqing Economic Circle but also offers theoretical and empirical support for global research and practice on urban–rural integration. Additionally, it proposes targeted policy recommendations. [ABSTRACT FROM AUTHOR]

Investigating regional connections and their influencing factors from the perspective of "flow" space is one of the foundations of promoting regional development. In this article, the data we used includes actual highway passenger flow data, National Polar-orbiting Partnership/Visible Infrared Imaging Radiometer Suite (NPP/VIIRS) nighttime light remote sensing data, and socioeconomic data. We analyzed the spatial distribution pattern, connection intensity and spatial autocorrelation of highway passenger flow in Chongqing during the working day, weekend and May Day and revealed the influencing factors by means of a geographic detector. Three key conclusions resulted from this research. First, highway passenger flow in Chongqing districts exhibits spatial agglomeration that is clearly higher in western Chongqing than in eastern Chongqing and forms an obviously dual-core "star" structure, with the main urban area and Wanzhou serving as the core. Second, a factor detector notes that the nighttime light area index (0.9251, 0.9512, 0.9541) has the strongest explanatory power for the spatial differentiation of passenger traffic in Chongqing districts, which is the key factor. Third, interaction detection shows that the interaction between the two factors displays an enhancement effect at different times. The nighttime light area index shows the strongest explanatory power under the synergy of tourist attractions, which are 0.9850, 0.9903 and 0.9908. But the per capita GDP and highway mileage have the most obvious enhancement effect after interaction (0.9544, 0.9661, 0.9652). Therefore, in future planning and development, we should pay attention to cooperation and exchanges between districts and use the nighttime light area index as an important reference factor to provide a scientific basis for the construction of public transport and economic construction in Chongqing. [ABSTRACT FROM AUTHOR]