Located in the western hinterland,Southwest China is a typical mountainous area covered by plateaus,mountains and hills.Its ruggedness hinders regional internal and external connections,and its poor transportation inf...Located in the western hinterland,Southwest China is a typical mountainous area covered by plateaus,mountains and hills.Its ruggedness hinders regional internal and external connections,and its poor transportation infrastructure has long constrained the socioeconomic development of Southwest China.Based on the GIS transportation database,this paper explored the spatiotemporal evolution and characteristics of the land transportation networks and the accessibility of Southwest China from 1917 to 2017.Regional accessibility in Southwest China has significantly improved,and transportation infrastructure has gradually integrated the transportation circles of the52 central cities.The transportation network has followed an evolutionary process from a"hub-spoke pattern"to a"network pattern",while the construction of a high-speed railway(HSR)has brought about significant spatial polarization.We argue that innovation in transportation technology is one of the most effective factors for promoting a significant change in regional accessibility.In addition,the spatial distribution and evolution of accessibility in Southwest China presents a verticalcharacteristic that distinguishes it from the plains,as the spillover effects of new transportation infrastructure on accessibility improvement are partly offset by the mountainous terrain.Additionally,in Southwest China,there is significant"path dependence"in the evolution of the transportation network,since a large portion of the population is concentrated along transportation corridors in mountainous areas.展开更多
The serious degradation of the ecological environment and the rapid expansion of stone desert have had a serious effect on the economic development of karst and rock-naked mountain areas in Southwest China. Moreover, ...The serious degradation of the ecological environment and the rapid expansion of stone desert have had a serious effect on the economic development of karst and rock-naked mountain areas in Southwest China. Moreover, these areas are still at the initial stage of industrialization, characterized by a greater significance of agriculture to the economy, face sharp contradictions among the population, the arable land and resources, and are suffering because of a shortage of investment. On the basis of this current situation, three recommendations are made in this article: "coordinating the relations among grain, ecology, population and economic development", "increasing the input of science and technology", and "adopting policies consistent with social equity in areas of poverty".展开更多
Emergency road networks(ERNs),an important part of local disaster prevention systems,can provide security to residents and their property.Exploring the ERNs structure is of great significance in terms of promoting dis...Emergency road networks(ERNs),an important part of local disaster prevention systems,can provide security to residents and their property.Exploring the ERNs structure is of great significance in terms of promoting disaster prevention and establishing road safety in dangerous mountainous areas.This study considered the ERNs of the Kangding section of the Dadu River Basin as the area for a case study.Complex Network Analysis was used to examine the relationship between the four characteristic indicators of mountain roads and the degree of earthquake impacts under the Lushan,Wenchuan,and Kangding Earthquake scenarios.Based on the analysis results,the southwest mountain road network was evaluated;then,computer simulations were used to evaluate the structural changes in the road network after index changes.The network was optimized,and the corresponding emergency avoidance network was proposed to provide a reference for the establishment of the mountainous ERN.The results show that the overall completeness of the mountainous ERNs in Southwest China is poor and prone to traffic accidents.Moreover,the local stability is poor,and the network is susceptible to natural hazards.The overall structure of the road network is balanced,but that of certain road sections is not.Road sections with different attributes present a“gathering-scattering”spatial distribution,i.e,some sections are clustered together while others are far apart.Accordingly,a planning optimization strategy is proposed to better understand the complexity and systematic nature of the mountainous ERN as a whole and to provide a reference for disaster prevention and mitigation planning in mountainous regions in Southwest China.展开更多
In mountainous areas, it is the undulant terrain, various types of geomorphic and land use that make the remote sensing images great metamorphism. Moreover, due to the elevation, there are many areas covered with shad...In mountainous areas, it is the undulant terrain, various types of geomorphic and land use that make the remote sensing images great metamorphism. Moreover, due to the elevation, there are many areas covered with shadow, clouds and snow that make the images more inaccurate. As a result, it would be very difficult to carry out auto-classification of RS images in these areas. The study took Southwest China as the case study area and the TM images, SPOT images as the basic information sources assisted by the auxiliary data of DEM, NDVl, topographical maps and soil maps to preprocess the images. After preprocessing by topographic correction and wiping off clouds, snow and shadows, all the image data were stacked together to form the images to be classified. Then, the research used segmentation technology and hierarchical method to extract the main types of land use in the area automatically. The results indicated that the qualitative accuracies of all types of land use extracted in Southwest China were above 90 percent, and the quantitative accuracies was above 86 percent. The goal of reducing workloads had been realized.展开更多
基金supported by the National Natural Science Foundation of China(Grants No.41671159)Fundamental Research Funds for the Central Universities for funding(Grants No.XDJK2018B011)Major Projects on Philosophy and Social Sciences of Chongqing Education Commission(Grants No.19SKZDZX08)。
文摘Located in the western hinterland,Southwest China is a typical mountainous area covered by plateaus,mountains and hills.Its ruggedness hinders regional internal and external connections,and its poor transportation infrastructure has long constrained the socioeconomic development of Southwest China.Based on the GIS transportation database,this paper explored the spatiotemporal evolution and characteristics of the land transportation networks and the accessibility of Southwest China from 1917 to 2017.Regional accessibility in Southwest China has significantly improved,and transportation infrastructure has gradually integrated the transportation circles of the52 central cities.The transportation network has followed an evolutionary process from a"hub-spoke pattern"to a"network pattern",while the construction of a high-speed railway(HSR)has brought about significant spatial polarization.We argue that innovation in transportation technology is one of the most effective factors for promoting a significant change in regional accessibility.In addition,the spatial distribution and evolution of accessibility in Southwest China presents a verticalcharacteristic that distinguishes it from the plains,as the spillover effects of new transportation infrastructure on accessibility improvement are partly offset by the mountainous terrain.Additionally,in Southwest China,there is significant"path dependence"in the evolution of the transportation network,since a large portion of the population is concentrated along transportation corridors in mountainous areas.
文摘The serious degradation of the ecological environment and the rapid expansion of stone desert have had a serious effect on the economic development of karst and rock-naked mountain areas in Southwest China. Moreover, these areas are still at the initial stage of industrialization, characterized by a greater significance of agriculture to the economy, face sharp contradictions among the population, the arable land and resources, and are suffering because of a shortage of investment. On the basis of this current situation, three recommendations are made in this article: "coordinating the relations among grain, ecology, population and economic development", "increasing the input of science and technology", and "adopting policies consistent with social equity in areas of poverty".
基金jointly supported by the National Key R&D Program of China(2018YFD1100804)。
文摘Emergency road networks(ERNs),an important part of local disaster prevention systems,can provide security to residents and their property.Exploring the ERNs structure is of great significance in terms of promoting disaster prevention and establishing road safety in dangerous mountainous areas.This study considered the ERNs of the Kangding section of the Dadu River Basin as the area for a case study.Complex Network Analysis was used to examine the relationship between the four characteristic indicators of mountain roads and the degree of earthquake impacts under the Lushan,Wenchuan,and Kangding Earthquake scenarios.Based on the analysis results,the southwest mountain road network was evaluated;then,computer simulations were used to evaluate the structural changes in the road network after index changes.The network was optimized,and the corresponding emergency avoidance network was proposed to provide a reference for the establishment of the mountainous ERN.The results show that the overall completeness of the mountainous ERNs in Southwest China is poor and prone to traffic accidents.Moreover,the local stability is poor,and the network is susceptible to natural hazards.The overall structure of the road network is balanced,but that of certain road sections is not.Road sections with different attributes present a“gathering-scattering”spatial distribution,i.e,some sections are clustered together while others are far apart.Accordingly,a planning optimization strategy is proposed to better understand the complexity and systematic nature of the mountainous ERN as a whole and to provide a reference for disaster prevention and mitigation planning in mountainous regions in Southwest China.
基金Supported by the National Public Welfare Project on Environmental Protection (2007KYYW21)the Program of National Science and Technology research(2006BAC01A01-05)
文摘In mountainous areas, it is the undulant terrain, various types of geomorphic and land use that make the remote sensing images great metamorphism. Moreover, due to the elevation, there are many areas covered with shadow, clouds and snow that make the images more inaccurate. As a result, it would be very difficult to carry out auto-classification of RS images in these areas. The study took Southwest China as the case study area and the TM images, SPOT images as the basic information sources assisted by the auxiliary data of DEM, NDVl, topographical maps and soil maps to preprocess the images. After preprocessing by topographic correction and wiping off clouds, snow and shadows, all the image data were stacked together to form the images to be classified. Then, the research used segmentation technology and hierarchical method to extract the main types of land use in the area automatically. The results indicated that the qualitative accuracies of all types of land use extracted in Southwest China were above 90 percent, and the quantitative accuracies was above 86 percent. The goal of reducing workloads had been realized.
