Search

The analysis of the spatial connection and structural characteristics evolution of the railway passenger transport network in Chengdu-Chongqing Economic Circle is of great significance to the future network construction and layout optimization. This paper constructs the railway passenger transport network of Chengdu-Chongqing Economic Circle based on the 46 863 617 railway passenger transport data, and uses GIS spatial analysis and social network analysis methods to analyze the space-time evolution of railway passenger transport links, the evolution of structure characteristics and the impact of network structure on economy and population in continuous time series. The results show that the polarization of railway passenger transport links in Chengdu Chongqing Economic Circle is obvious, and the passenger transport flow is mainly concentrated in Chengdu, followed by Mianyang, the main districts of Chongqing and Deyang, and other cities account for less than 20% of the passenger transport flow. The density of railway passenger transport network in Chengdu-Chongqing Economic Circle is increasing year by year, but it is still at a low level. The railway passenger transport network has a low average path length and a high average clustering coefficient, and it is characterized by a small world. The degree centrality and betweenness centrality of Chengdu and the main districts of Chongqing are far more than those of other cities. The accessibility of railway passenger transport in Chengdu-Chongqing Economic Circle is largely due to the intermediary role of Chengdu and the main districts of Chongqing. There is no railway passenger transport connection between most cities. The degree centrality, proximity centrality and intermediate centrality have positive effects on GDP, and pass the 1% significance level test. The degree centrality and intermediate centrality have negative impacts on the population, and pass the significance level tests of 5% and 10% respectively. Cities in the central position are not conducive to the permanent residence of the population. [ABSTRACT FROM AUTHOR]

Purpose: Rational location of emergency medical service (EMS) facilities could improve access to EMS, and thus assist in saving patients' lives and improving their health outcomes. A considerable amount of spatial optimization research has been devoted to the development of models to support location planning in the context of EMS, with extensive applications in policy making around the world. However, in China, studies on the location of EMS facilities have not been paid enough attention to, let alone their practical applications. This paper conducted location optimization for EMS facilities in Chengdu, one of the biggest cities in southwest China with more than 16.5 million population, aiming to optimize the EMS system by adding (upgrading) a minimum number of EMS facilities to achieve a given population coverage. Methods: Location optimization was conducted according to regional health policy goal for the EMS system in Chengdu, China, 2017. The nearest-neighbor approach was used to calculate the shortest travel time based on geographical information system (GIS). The location set covering model was used to formulate the optimization problem under China's context, and genetic algorithm (GA) was employed to determine the optimized locations. Results: The results showed that a minimum number of 55 new facilities were required to upgrade to EMS facilities to achieve the policy goal of 90% population coverage of EMS within 15 minutes. Access to EMS also improved substantially in terms of shortest travel time after facility upgrading. The weighted median shortest travel time to EMS facilities in Chengdu decreased by 14.57%, from 6.45 minutes to 5.51 minutes. Conclusion: Our study showed that the solution could effectively achieve the policy goal of population coverage with a minimum number of new EMS facilities. Our findings would support evidence-based decision-making in future EMS planning in China. [ABSTRACT FROM AUTHOR]

One of the most important variables that leads to effective individual and group tours is the tourism route planning approach, which enables tourists to engage with tourism with ease, speed, and safety. However, current methods of designing tourist routes have some glitches, such as relying only on external objectives to find the best route. In this paper, a novel urban tourism path planning method based on a multiobjective genetic algorithm is proposed. The main goal of this paper is to enhance the accuracy of the genetic algorithm (GA) by adopting new parameters and selecting the optimal tourism path by combining external and internal tourist site potentials. Moreover, the GA and analytical hierarchy process (AHP) were used in our proposed approach to evaluate urban tourism route planning under multiple conflicting objectives. To visualize and execute the proposed approach, the geographic information system (GIS) environment was used. Our suggested approach has been applied to develop the tourist road network of Chengdu City in China. Compared with existing tourism path planning approaches, our proposed approach is more accurate and straightforward than other approaches used to choose routes. [ABSTRACT FROM AUTHOR]

The design and optimization of urban form has always been a hot topic in urban planning and development research. Besides, the creation of continuous vitality in urban areas is of critical importance in the development of urbanization. However, due to the lack of data, it is difficult to measure the effects of urban form on neighborhood vibrancy. Additionally, no uniform conclusion has been drawn regarding to what degree urban form can contribute to neighborhood vibrancy. Taking advantage of emerging new data sources, the depth and breadth of related research can now be improved. Therefore, this paper uses high-precision positioning social media check-in data to approximate the vibrancy of 658 neighborhoods, and uses a geographical information system (GIS) to quantitatively measure the urban form indicators in the central area of Chengdu City, China. A quantitative exploration and analysis of the relationships between neighborhood vibrancy and urban form is conducted. The results of three regression models considering different explanatory variables show that socio-economic factors account for approximately 23% of neighborhood vibrancy. In addition, the correlation between the shape characteristics of a neighborhood and the vibrancy is weak. However, when the inner urban form indicators of neighborhoods are introduced into the regression model, the goodness of fit (R2) is nearly doubled. This finding indicates that strong associations exist between urban form and neighborhood vibrancy. Specifically, building density and functional diversity are positively correlated with neighborhood vibrancy. Unlike existing studies, this study finds that the road network within the neighborhood plays a positive role in the creation of neighborhood vibrancy. However, the impact of a road density indicator is not as powerful as the impacts of building density and functional diversity. This research can help urban designers to better design urban environments. [ABSTRACT FROM AUTHOR]

TOptimization of regional landscape pattern is significant for improving function and value of ecosystem, and restraining the expansion of urban layout. Taking Chengdu City for example, this paper applied RS and GIS techniques, landscape indexes and ecological service function evaluation to further analyze the temporal and spatial characteristics of landscape pattern and spatial differences of regional ecologjcal functions, and on this basis, identified the spatial distribution of ecological source lands. Based on the long-term objective of building Chengdu into a modern garden city, this paper applied the accumulative cost distance model and introduced garden city theory to construct regional ecological corridors and ecological nodes, and explored the approaches of optimizing landscape pattern of modern garden city. The results showed that a great deal of arable land has been transferred to construction land in the urbanization; intensity of regional ecological functions showed obvious spatial differences; ecological source lands were mainly distributed in the Longmen Mountain, the Qionglai Mountain, the Changqiu Mountain and the Longquan Mountain; according to actual conditions of the study area, the road ecologjcal corridors, river corridors and agricultural corridors in the layout of "four rings and six radial corridors" were constructed; ecological nodes dominated by intersection, wetland and forest park were formed. This research method and results are significant references for building Chengdu into a modern garden city. [ABSTRACT FROM AUTHOR]

The expansion of urban areas and the increase in the number of buildings and urbanization characteristics, such as roads, affect the meteorological environment in urban areas, resulting in weakened pollutant dispersion. First, this paper uses GIS (geographic information system) spatial analysis technology and landscape ecology analysis methods to analyze the dynamic changes in land cover and landscape patterns in Chengdu as a result of urban development. Second, the most appropriate WRF (Weather Research and Forecasting) model parameterization scheme is selected and screened. Land-use data from different development stages in the city are included in the model, and the wind speed and temperature results simulated using new and old land-use data (1980 and 2015) are evaluated and compared. Finally, the results of the numerical simulations by the WRF-Chem air quality model using new and old land-use data are coupled with 0.25° × 0.25°-resolution MEIC (Multi-resolution Emission Inventory for China) emission source data from Tsinghua University. The results of the sensitivity experiments using the WRF-Chem model for the city under different development conditions and during different periods are discussed. The meteorological conditions and pollution sources remained unchanged as the land-use data changed, which revealed the impact of urban land-use changes on the simulation results of PM2.5 atmospheric pollutants. The results show the following. (1) From 1980 to 2015, the land-use changes in Chengdu were obvious, and cultivated land exhibited the greatest changes, followed by forestland. Under the influence of urban land-use dynamics and human activities, both the richness and evenness of the landscape in Chengdu increased. (2) The microphysical scheme WSM3 (WRF Single–Moment 3 class) and land-surface scheme SLAB (5-layer diffusion scheme) were the most suitable for simulating temperatures and wind speeds in the WRF model. The wind speed and temperature simulation results using the 2015 land-use data were better than those using the 1980 land-use data when assessed according to the coincidence index and correlation coefficient. (3) The WRF-Chem simulation results obtained for PM2.5 using the 2015 land-use data were better than those obtained using the 1980 land-use data in terms of the correlation coefficient and standard deviation. The concentration of PM2.5 in urban areas was higher than that in the suburbs, and the concentration of PM2.5 was lower on Longquan Mountain in Chengdu than in the surrounding areas. [ABSTRACT FROM AUTHOR]

Copyright of Professional Geographer is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Research on the service values of urban ecosystems is a hot topic of ecological studies in the current era of rapid urbanization. To quantitatively estimate the ecosystem service value in Chengdu, China from the perspectives of natural ecology and social ecology, the technologies of remote sensing (RS) and geographic information system (GIS) are utilized in this study to extract the land use type information from RS images of Chengdu in 2003, 2007, 2013 and 2018. Subsequently, a driver analysis of the ecosystem services of Chengdu was performed based on socioeconomic data from the last 16 years. The results indicated that: (1) from 2003 to 2018, the land utilization in Chengdu changed significantly, with the area of cultivated lands, forest lands and water decreasing remarkably, while the area of construction lands dramatically increased. (2) The ecosystem services value (ESV) of Chengdu decreased by 30.92% in the last 16 years, from CNY 2.4078 × 1010 in 2003 to CNY 1.6632 × 1010 in 2018. Based on a future simulation, the ESV is further predicted to be reduced to CNY 1.4261 × 1010 by 2033. (3) The ESV of Chengdu showed a negative correlation with the total population, the urbanization rate and the per capita GDP of the region, indicating that the ESV of the studied region was inter-coupled with the socioeconomic development and can be maintained at a high level through rationally regulating the socioeconomic structure. [ABSTRACT FROM AUTHOR]