Spatial differentiation and dynamic mechanism of micro-geomorphology based on acoustic spectrum data of the Huanghe(Yellow)River Delta

Submarine micro-geomorphology is a geo-morphological type occurring in shallow and surface areas of seabed.The combined relationships and distribution of the micro-geomorphology indirectly reflect coupling relationships among the sediment deposition,dynamic environment,and geomorphologic evolution.Spatial differentiation and dynamic changes in micro-geomorphology were studied based on acoustic data interpretation from a wide range(3200 km^(2))of the Huanghe(Yellow)River delta(HRD).The combination of the sub-bottom profiler and the side-scan sonar methods allowed for the identification of submarine shallow micro-geomorphologic types,as well as their scale and spatial distributions.There were seven typical micro-geomorphologic features in the shallow and surface areas of the HRD,including buried ancient channels,stratigraphic disturbances,scour troughs,sand waves,pits,erosional remnants,and sand spots.The coupling and superposition of the sediment,sediment characteristics,seabed scouring and silting,and hydrodynamic conditions of the Huanghe River had combined effects on the patterns of micro-geomorphologic types,characteristics,and ranges.From the perspective of acoustic profile interpretations,the scale,range,and spatial locations of the microgeomorphology in the HRD revealed seasonal variation characteristics,and the spatial distributions displayed significant regional differentiation characteristics.In addition,strong stratigraphic disturbances and areas with densely distributed buried ancient channels reflected the activity and instability of the submarine shallow strata.Through the interpretation of the sub-bottom profile detection data,the diversion processes of the flow paths in the lower reaches of the Huanghe River were obtained for a certain historical period in the coastal waters of the HRD.This study further clarified the relationships between the micro-geomorphologic features and spatial combinations,which is important for research on micro-geomorphologic features and their dynamic mechanisms.

SPATIAL DIFFERENTIATION OF LAND TRANSFER——Case Study of Shanghai, Nanjing and Taizhou in Changjiang River Delta

The policy of land transfer has greatly influenced the macro economy of China with the commencement of another innovation of land use system. Therefore, it is urgent to put forward some rational and feasible suggestions for local government to manage the market of land transfer. Moreover, it is important in the field of study on agricultural land use change to analyze the spatial differentiation and structural specification of land transfer, which are caused by rural households＇ behavior. This paper selected I l factors covering four aspects of rural households＇ family structure, family location, family income structure and the natural quality of land resources, all of which influence the behavior differentiation of rural households, to establish the index model indicating spatial differentiation of land transfer. Results show that the spatial differentiation of land transfer can be divided into four degrees and three categories through analyzing rural households＇ questionnaires from Shanghai, Nanjing and Taizhou in the Changjiang （Yangtze） River Delta. Since up to 80% of rural households belong to middle degrees, it can be concluded that the rural land market develops evenly in the study areas. And it is also indicated that the natural quality of land resources and the maximum income of rural land are most important factors influencing the spatial differentiation of land transaction. Considering different factors, the countermeasures can be carried out to enhance the spatial differentiation of land transfer so as to promote economic development and social security of rural China. All in all, both micro- factors and macro-factors influencing rural households＇ behavior of rural land transfer should be taken into account in order to make spatial differentiation and structural specification of rural land transfer notable.

Quantitative evaluation and spatial differentiation of eco-environmental livability in Zhejiang Province, China

The scientific analyses of the spatial patterns of regional eco-environment livability,along with the explorations of the correlations between ecoenvironments and population and economic activity distributions,are of major significance in the guidance of the coordinated development between social economies,natural resources,and environments.In this study,the topography,climate,hydrology,land cover,air quality,and the dangers presented by natural hazards in the study area were investigated in order to establish an evaluation model for the regional eco-environmental livability.Then,the observed spatial patterns and regional differences in the eco-environmental livability,as well as their relationships with the distributions of population and economic activities in Zhejiang Province,were investigated.The results showed that the ecoenvironmental livability in Zhejiang Province displayed a gradual decreasing trend from southwest to northeast,as well as from the mountains to the hills,valleys,and plains areas.During the compartmentalization of the eco-environmental livability,it was observed that the lowest livable area covered the largest population,accounting for approximately 29.64%of the total population in the study area.The higher livable areas covered the widest land areas,accounting for approximately 26.15%of the total area.Moreover,it was found that the eco-environmental livability in the mountain areas was higher than that in the plain areas in Zhejiang Province.Furthermore,the ecoenvironmental livability was found to have a significant exponential relationship with the population and GDP densities of Zhejiang Province,with the R^2 of the curve-fittings reaching 0.835 and 0.656,respectively.However,it was determined that the coefficient of the exponential function was negative,which indicated that a strong negative relationship existed between the eco-environmental livability and densities of the population and economic activities.It was assumed that the impacts of anthropogenic factors were the fundamental causes of this negative correlation.This study introduced two new factors(air quality and natural hazards)into the evaluation framework of eco-environmental livability.As a result,a more comprehensive model was established for the evaluation of eco-environmenta livability in certain segments of the study area Additionally,the correlation between ecoenvironment livability and human activities was discussed in-depth,which can potentially provide theoretical and practical guidance for the implementation of eco-livability in China,and possibly even those of other vast developing countries.

Spatial differentiation in stable isotope compositions of surface waters and its environmental significance in the Issyk-Kul Lake region of Central Asia

Stable isotope values of oxygen （180） and hydrogen （2H） of surface waters were used to study the origin and environmental significanees in the Issyk-Kul basin of Kyrgyzstan in Central Asia, which is the most important intermountain basin in the modern Tien Shan orogen. This study is the first analysis of hydrochemical spatial differentiation in the stable isotopes of surface waters in this watershed. 75 samples were collected from rivers, springs, lakes, rain and snow during the rainy season in July and August of 2o16. Stable isotopes of 180 and 2H were studied for all samples, and cation ratios （Sr/Ca and Mg/Ca） were also determined for lake water samples. Stable isotope values from precipitation scattered around the Local Meteoric Water Line （determined from Urumqi Station of the global network of isotopes in precipitation （GNIP））, together with values of the Deuterium excess parameter （d） from 15.3‰ to 30.5‰, with an average of 19.8‰, indicating that the moisture sources are primarily from regions with low relative humidity. The 8180 and 52H values were significantly different between the river and lake samples, indicating that regional evaporation caused the isotopic enrichment of lake water. Geospatial autocorrelation, measured by Moran＇s I coefficient, indicated weak spatial autocorrelation within stable isotopes of oxygen and hydrogen in the surface waters of the studied area, which is primarily an effect of climate during the water chemistry evolution. The cation ratios Sr/Ca and Mg/Ca in lake water samples were not correlated with the concentration of total dissolved solids, but did show correlation with stable isotopic values, which is significant for paleoenvironmental reconstruction.

GIS-based spatial differentiation of ethnic minority villages in Guizhou Province,China

The protection and development problems in ethnic minority villages have received great attention from the Chinese government.This study aims to systematically identify the spatial differentiation characteristics of ethnic minority villages and their influencing factors in Guizhou Province.Applying ArcGIS and GeoDa,a total of 1,014 ethnic minority villages in the four batches announced by the Ethnic and Religious Affairs Commission of Guizhou Province(272in the first batch,240 in the second batch,255 in the third batch,and 247 in the fourth batch)served as the research objects.Utilizing the economic development data in Guizhou Statistical Yearbook 2018-2020 for analysis,the coupling calculation of the spatial layout and economic development level of ethnic minority villages was conducted.The results indicate that the number of ethnic minority village points varies in spatial distribution with remarkable agglomeration.The spatial equilibrium distribution of ethnic minority villages in the province is imbalanced.The kernel density is characterized by independent single kernel centers with sporadic distributions of subcenters and an echelon distribution whole.The spatial complexity distribution indicates that ethnic minority villages in Guizhou possess unequal characteristics,and the fractal of the system structure is more complicated.The findings reveal that the spatial distribution of ethnic minority characteristic villages in Guizhou is highly consistent with that of ethnic minorities in Guizhou.The distribution is the combined results of geographical factors and socialeconomic factors.Most ethnic minority characteristic villages in Guizhou Province are located in areas with complex terrain,inconvenient transportation,and relatively backward economic development.Based on the current geospatial distribution of ethnic minority villages,the present study will provide remarkable implications for the Chinese government to implement the Rural Revitalization Strategy from several key aspects.The Chinese government should establish a protection and development mechanism in ethnic minority villages and strive to enhance the characteristics of ethnic cultural industries.Meanwhile,the"integration of culture and tourism"should be taken as the development strategy while the industry should support rural economic development and help eliminate poverty.This is of crucial practical significance to national unity and rural revitalization in China.

Spatial Differentiation Characteristics of Human Settlements and Their Responses to Natural and Socioeconomic Conditions in the Marginal Zone of an Uninhabited Area,Changtang Plateau,China

The Changtang Plateau(CTP)in Qinghai-Tibet Plateau of China is one of the top-10 uninhabited areas with the most important ecological value in the world.It is of great academic and practical significance to carry out research on human settlements in the marginal zones of the uninhabited areas to promote harmonious coexistence between humans and nature on the CTP.Using high-definition remote-sensing images to visually interpret and identify settlement-patch data,combined with field investigations,this study explores the spatial characteristics of human settlements in Shuanghu and Nyima counties and their responses to natural and socioeconomic conditions in the hinterland of the CTP.Findings reveal that the scale of human settlements on the CTP is extremely small,and density is very sparse.Settlements on the CTP primarily consist of several households,with some containing more than a dozen households,or are sub-village scale.Socioeconomic development is low and socioeconomic factors have a weak influence on the settlement layout on the CTP.Natural factors are the core elements affecting the layout of human settlements on the CTP.Settlements tend to occur on low mountains,gentle slopes,and areas with high average annual temperatures.Careful settlement site selection can help to mitigate the impact of natural disasters.To meet the needs of grazing,settlement layouts must typically have a high-quality grassland orientation.Riverbanks are key settlement areas,and settlement sites are often far away from alpine salt lakes.The characteristics of settlements on the CTP and their responses to environmental conditions significantly differ from those of human settlements in low-altitude inland areas.

Spatial differentiation pattern of interregional migration in ethnic minority areas of Yunnan Province, China

Interregional migration has broad and far-reaching impacts on regional urbanization process in ethnic minority areas of Southwest China.The previous literature of interregional migration paid less attention on the ethnic minority areas with fragile geographical feature and marginal socio-economic context in the developing world due to the dearth of reliable data.Based on the 2015 national 1%population sampling survey at the village/community scale,taking Yulong Naxi Autonomous County,Yunnan Province,China as the case study,this paper analyzed the spatial differentiation pattern.The results showed that:(1)migration in Yulong Naxi Autonomous County exhibited obvious spatial differentiation characteristics in terms of population aggregation,population loss,migration direction,and migration activity;(2)the overall spatial differentiation of migration exhibited a"layer+sector"pattern in Yulong Naxi Autonomous County:the first layer was active areas with net inflows(<20 km from the seat of the county government),the second layer was inactive areas(within 20–60 km of the seat of the county government),and the third layer was a mixed"layer+sector"zone(>60 km to the seat of the county government),comprised of inactive areas and active areas with net outflows;(3)the spatial differentiation pattern of migration was highly correlated with the regional contexts including the regional economic development,regional transportation accessibility and regional social development,while regional physical geographical factors had insignificant relationships with the migration pattern.

Analyzing the Causes of Spatial Differentiation of the Traditional Villages in Gansu Province, Western China

The study and protection for traditional villages are very important for us to protect Chinese historical and cultural heritage. Data show that under the condition of rapid urbanization. The number and coverage of traditional villages in western China are decreasing. It is impossible to effectively protect a large number of rural settlements at the bottom of China’s traditional settlement system. Therefore, it is necessary to explore the spatial survival status of traditional villages and protect them comprehensively and extensively. Using the digital elevation model (DEM) data of traditional villages in Gansu Province, China, published by the Ministry of Housing and Urban Development and the attribute data obtained by the Statistics Bureau of Gansu Province, China, the nuclear density, the Mulan indices, the correlations between the heights and the centers are calculated and used to study the spatial different characteristics of the villages, and a number of results have been achieved: 1) In spatial differentiation, the spatial agglomeration of the villages is obvious and different, which can be seen by the distribution of the villages from along the upper reaches of the Yellow River to the southeast, and the distribution of prefecture-level cities is related to the landforms. 2) In vertical spatial distribution, the span of the altitude data is large. Among the villages, the Zagana Village in Diebu County of Gannan City is the highest and the Zhengjiashe Village in Bingkou Town of Longnan City is the lowest. With the increase of altitude, the number of traditional villages generally shows a tendency of decrease. 3) The spatial differentiation of the traditional villages has a clear normal distribution with the elevation, and the spatial differentiation is low, showing a distinct gourd-like structure;the eastern and southern regions are more concentrated, while the northern and western regions are less concentrated. 4) The spatial differences of the traditional villages have the characteristics of regional differences, which are weakly related to the distance between the central cities and occur mainly in the Longnan mountain regions, the Loess Plateau in the middle of Longzhong and the Gannan plateau. The results of this study are a useful support in protection of traditional villages in provincial scale. It helps to enhance the integrity and systematicness of the protection of the spatial distribution of traditionally villages. The Chinese government had put forward the “Poverty alleviation strategy” to help Gansu Province to get out of the villages’ trouble. Viewed from this angle, the research for effective patterns of traditional villages’ protection and exploitation plays a crucial role in the development of China’s “Poverty Alleviation Strategy”.

Spatial Differentiation,Typological Structure,and Influencing Factors of A-grade Scenic Spots in China

Tourism scenic spots serve as direct attractions for tourists and crucial drivers for the transformation and upgrading of the tourism industry,so they play an irreplaceable role in the development of the tourism sector.The quantity and grades of A-grade scenic spots are the mainstay of competition in various tourism markets,and their spatial layout is very important for the development of regional tourism.Using 11970 A-grade scenic spots in China as the research sample,and methods such as the Nearest Neighbor Index Method,Kernel Density Estimation Method,and Grid Dimension Method,the spatial distribution,typological structure,and influencing factors of A-grade tourist attractions were analyzed to identify the main natural,economic,and social factors influencing the spatiotemporal pattern of A-grade scenic spots.The results indicated that China’s A-grade scenic spots exhibit clustering characteristics in their spatial distribution.The kernel density center shows a spatial pattern of“multiple cores,with secondary cores surrounding,and a gradual decrease”.The spatial structure is fractal and complex,with significant regional differences and a notable scale-free range.The types of tourist destinations and products exhibit distinct regional features,with a higher concentration of scenic spots in the regions in South China and East China,which are characterized by favorable natural and economic conditions and convenient transportation.A-grade scenic spots are densely distributed around the Beijing-Tianjin-Hebei region and the eastern regions such as Shanghai,Zhejiang,and Jiangsu provinces.Analyzing the spatial distribution characteristics of A-grade scenic spots in China contributes to our understanding of the complexity of scenic spot layout and spatial connections,which provides a basis for optimizing the layout of tourism development within regions,the rational allocation of resources,enhancing the quality and efficiency of the tourism industry,and promoting sustained and healthy regional economic development.It is conducive to the strategic work of tourism development and rural revitalization in China,and serves as a reference for decision-making.

Residential Differentiation Based on Reachability and Spatial Clustering : A Case Study of the Main Urban Area of Wuhan City

The differentiation of urban residential space is a key and hot topic in urban research, which has very important theoretical significance for urban development and residential choice. In this paper, web crawler technology is used to collect urban big data. Using spatial analysis and clustering, the differentiation law of residential space in the main urban area of Wuhan is revealed. The residential differentiation is divided into five types: "Garden" community, "Guozi" community, "Wangjiangshan" community, "Yashe" community, and "Shuxin" community. The "Garden" community is aimed at the elderly, with good medical accessibility and open space around the community. The "Guozi Community" is aimed at young people, and the community has accessibility to good educational and commercial facilities. The "Wangjiangshan" community is oriented towards the social elite group, with beautiful natural living environment, close to the city core, and convenient transportation. The "Yashe" community is aimed at the general income group, and its location is characterized by being adjacent to commercial districts and convenient transportation. The "Shuxin" community is aimed at the middle and lower income groups, far from the city center, and the living environment quality is not high.

Spatial Differentiation of Rural Touristization and Its Determinants in China: A Geo-detector-based Case Study of Yesanpo Scenic Area

Tourism has emerged as a major driving force in the growth and expansion of rural settlements. After several studies revealed spatial differentiation of touristization among rural settlements, studies were conducted to explain this phenomenon. However, most of these studies explained spatial differentiation of rural touristization in a qualitative way. More robust and detailed quantitative results are needed to evaluate the relative roles of different factors. In this study, which takes Yesanpo tourism as a case study, the Geo-detector method was introduced to evaluate determining factors of rural touristization. Results show that ＂distance to core entry＂, ＂tourist number and sojourn time＂, and ＂distance to the nearest scenic area＂ have had a strong effect on the rural touristization in Ye- sanpo, whereas ＂distance to river＂, ＂elevation＂, ＂distance to main road＂, and ＂slope＂ have had a weak influence. The latter did, however, contribute a lot to touristization when interacting with ＂distance to core entry＂, ＂tourist number and sojourn time＂, and ＂distance to the nearest scenic＂, indicating the importance of these four factors. Higher rural touristization occurred in the zone near the core entry, with many tourists, long sojourn times, and proximity to the scenic area.

NDVI spatial pattern and its differentiation on the Mongolian Plateau

GIMMS NDVI database and geo-statistics were used to depict the spatial distribution and temporal stability of NDVI on the Mongolian Plateau.The results demonstrated that:(1) Regions of interest with high NDVI indices were distributed primarily in forested mountainous regions of the east and the north,areas with low NDVI indices were primarily distributed in the Gobi desert regions of the west and the southwest,and areas with moderate NDVI values were mainly distributed in a middle steppe strap from northwest to southeast.(2) The maximum NDVI values maintained for the past 22 years showed little variation.The average NDVI variance coefficient for the 22-year period was 15.2%.(3) NDVI distribution and vegetation cover showed spatial autocorrelations on a global scale.NDVI patterns from the vegetation cover also demonstrated anisotropy;a higher positive spatial correlation was indicated in a NW-SE direction,which suggested that vegetation cover in a NW-SE direction maintained increased integrity,and vegetation assemblage was mainly distributed in the same specific direction.(4) The NDVI spatial distribution was mainly controlled by structural factors,88.7% of the total spatial variation was influenced by structural and 11.3% by random factors.And the global autocorrelation distance was 1178 km,and the average vegetation patch length(NW-SE) to width(NE-SW) ratio was approximately 2.4:1.0.

Effect of land prices on the spatial differentiation of housing prices:Evidence from cross-county analyses in China

This study analyzes the spatial patterns and driving forces of housing prices in China using a 2,872-county dataset of housing prices in 2014.Multiple theoretical perspec-tives on housing demand,supply,and market,are combined to establish a housing price model to explore the impact of land prices on housing prices.The relative impacts of land prices on housing prices at different administrative levels are then analyzed using the geo-graphical detector technique.Finally,the influencing mechanism of land prices on housing prices is discussed.The main conclusions are as follows.(1)Housing prices have a pyra-mid-ranked distribution in China,where higher housing prices are linked to smaller urban populations.(2)Land prices are the primary driver of housing prices,and their impacts on housing prices vary over different administrative levels.To be specific,the effect of land prices is the strongest in the urban districts of provincial capital cities.(3)The internal influ-ence mechanisms for land prices driving housing prices are:topographic factors,urban con-struction level,the agglomeration degree of high-quality public service resources,and the tertiary industrial development level.The urban land supply plan(supply policies)is the in-trinsic driver that determines land prices in cities;through supply and demand,cost,and market mechanisms,land prices then impact housing prices.

Impact of urban landscape and environmental externalities on spatial differentiation of housing prices in Yangzhou City

In this study, housing prices data for residential quarters from the period 2001-2012 were used and Global Differentiation Index （GDI） was established to measure the overall differentiation trend in housing prices in Yangzhou City, eastern China. Then the influence of the natural landscape and environment on prices of global housing market and housing submarkets was evaluated by the hedonic price model. The results are shown as follows. （1） There have been increasing gaps among housing prices since 2001. In this period, the differentiation trend has shown an upward fluctuation, which has been coupled with the annual growth rate of housing prices. （2） The spatial distribution of residential quarters of homogenous prices has changed from clustered in 2001 into dispersed in 2012. （3） Natural landscape and environmental externalities clearly influence spatial differentiation of housing prices. （4） In different housing submarkets, the influence of natural landscape and environmental eternalities are varied. Natural landscape characteristics have significant impact on housing prices of ordinary commercial houses and indemnificatory houses, while the impact of environmental characteristics have obvious influence on housing prices of cottages and villas.

A comprehensive assessment of urban vulnerability and its spatial differentiation in China

The urban vulnerability poses a serious challenge to achieving sustainable devel- opment. With the concentration of the population and the economy, cities must manage the higher frequencies and risks of various hazards and are becoming more vulnerable. Re- search on the assessment and regulatory control of urban vulnerability is of great significance for both urbanization quality improvement and sustainable development in China or other countries in the world. Because of the complexity of cities and vulnerability concepts, existing studies have focused on different aspects of urban vulnerability. And the research content of urban vulnerability is scattered and relatively independent, leading to a lack of comparability among the research data and resulting in tremendous difficulties in summarizing the conclu- sions through comparison of independent research data. Therefore the goal of this study was to construct urban vulnerability index （UV/） from the perspective of sustainable development that could assess urban vulnerability comprehensively. In this study, we selected 10 subin- dexes involving 36 specific parameters from four aspects （resources, eco-environmental sys- tems, economics, and social development） to construct a comprehensive index system. We also established the standard values of measurements. Then we take 288 prefecture-level cities in China as a study area and evaluate its overall urban vulnerability and its spatial differentiation. Results indicate that urban vulnerability of China has a remarkable spatial differentiation of both ＂gradient distribution＂ and ＂clustered distribution＂; the extent of urban vulnerability corresponds to city size, the bigger the city, the lower its vulnerability; re- source-based cities are more vulnerable than comprehensive cities; a city＇s economic growth rate does not reflect the extent of its urban vulnerability. Further, we offer a few suggestions to cope with urban vulnerability in China.

Spatial Differentiation Pattern of Habitat Quality and Mechanism of Factors Influencing in Resource-based Cities:A Case Study of Tangshan City,China

The degradation of the eco-environment has been a challenge for sustainability in resource-based cities around the world.Although much attention has been drawn to this issue,few insights have been acquired regarding the spatial differentiation and mechanism of the factors influencing habitat quality in resource-based cities from the perspective of the interactions of natural and human factors.Using Tangshan City as a case study,this paper evaluates habitat quality by integrating Ecosystem Service Value Assessment and the InVEST-HQ model,identifies the spatial distribution of Tangshan’s habitat quality with spatial auto-correlation,and explores the influencing factors and their mechanism of influence on the spatial differentiation with the geographical detector model and Space production theory.The results show that:(1)The total value of the habitat quality in Tangshan City in 2019 was 3.45×10^(10) yuan,and the habitat quality value was 24435.05 yuan ha-1.The habitat quality value presents a clustered distribution pattern of"hot in the north and the south,cold from the center to the west".(2)On the county scale,Qianxi County had the best habitat quality and Lubei District had the worst habitat quality;Shangying Township had the highest average habitat quality and Kaiping Street had the lowest average habitat quality in the township unit.(3)The results of geographical detectors show that natural environmental conditions are the important basic factors affecting the spatial differentiation of habitat quality in Tangshan City,while urbanization and industrialization factors are the most important external forces driving the spatial differentiation of habitat quality.The contributions of average elevation,average slope,raw material industrial density,and population density to the spatial differentiation of habitat quality are all above 0.40.The interactions of any two factors on habitat quality are enhanced.Areas with concentrated populations,rich industrial resources,and convenient transportation become low-value habitat quality areas;while areas with beautiful landscape patterns,abundant precipitation,and a comfortable climate become high-value habitat quality areas.Space production theory can be used to explain the mechanism of the formation of the spatial differentiation of habitat quality.

Spatial Differentiation Characteristics and Driving Forces of Forest Transition:A Case Study of Zunyi City,Guizhou

Spatial differentiation in forest transition was measured in terms of space transition and function transition using the exploratory spatial data analysis method（ESDA） and data from 2004—2014 for Zunyi city,Guizhou province,China.The validity of factors affecting forest transition was analyzed by constructing radial basis function neural networks（RBFNN） based on the data processing system（DPS）.Our results will provide references for scientific understanding of the potential mechanism underlying forest transition in mountainous areas.We found that Global Moran＇s I of space transition and function transition of forest land was 0.0336 and 0.2323,respectively.This suggests a significant positive correlation in spatial distribution of space transition and function transition of forest land,and significant spatial aggregation.The Global Moran＇s I of function transition was higher than that of space transition,and the spatial aggregation characteristics of function transition were more significant than for space transition.The Global Moran＇s I at each time period tended to increase,and the spatial aggregation degree of the function transition and space transition was further enhanced.Hot and cold spots of space transition of forest land stably evolved,suggesting a minor spatial difference in forest land among different administrative units at the county level.The number of hot spots at the county level in function transition increased.Hot spots were intensively distributed at the western edge and continuously distributed in the northeast.The space transition and function transition of forest land were both greatly influenced by urbanization rate and second and third industries.The development of urbanization and industrialization was the main factor driving forest transition,suggesting a positive role of economic growth on forest transition in mountainous areas.The development of urbanization and industrialization is an effective approach to forest transition in mountainous areas.

Spatial differentiation and influence mechanism of the connection-distribution performance of urban high-speed railway hub in the Yangtze River Economic Belt

A transportation hub is the key link in the construction of the comprehensive three-dimensional transportation corridor of the Yangtze River Economic Belt,and is the basic factor responsible for the promotion of this belt.A high-speed railway hub has the“last kilometer of time-space compression”effect and is the key to building an efficient,convenient,modern,and comprehensive transportation system.This study constructed a model for measuring the connection-distribution performance of the high-speed railway hub,determined the connection-distribution performance of the urban high-speed railway hub in the Yangtze River Economic Belt,and analyzed its spatial differentiation characteristics,further revealed the influencing mechanism of the connection-distribution performance of the high-speed railway hub.The main results are as follows:(1)The connection-distribution performance of the high-speed railway hub in the Yangtze River Economic Belt presented an“olive-shaped pattern”grade structure with two small ends and a large middle section,that is,the number of high-speed railway stations with high performance and average performance was small,and the number of high-speed railway stations with good performance and medium performance was large.(2)The connection-distribution performance of the high-speed railway hub in the Yangtze River Economic Belt showed a regional differentiation pattern of“high in the east and low in the west”and“high in the north and low in the south”,and showed an urban agglomeration differentiation pattern of“high in the core areas but low in the marginal areas”;moreover,spatial differences were prominent in the distribution of nine evaluation indexes of the connection-distribution performance of the high-speed railway hub.(3)GDP,urbanization rate,city level,station passenger flow and frequency of shuttle bus were key driving factors affecting the connection-distribution performance of the high-speed railway hub.At the same time,there were significant differences in the key driving factors for the connection-distribution performance grades of high-quality,good,medium and average.

Spatial Distribution of Different Types of Villages for Rural Revitalization Strategy and Their Influencing Factors:A Case of Jilin Province,China

Village classification is the first step to implementing China’s rural revitalization(RR)strategy,and understanding the geographic differences in the distribution of village types helps to grasp the pathway of their unique development.This study spatialized9250 villages in Jilin Province(divided into six types)of China,and their distribution characteristics and influencing factors were examined using methods such as kernel density estimation,Ripley’s K function,the co-location quotient,and Geodetector.The results indicate that the spatial distribution balance and density of village types are different.All types of villages show an agglomeration distribution pattern,but the scale and intensity vary.There is a strong spatial association between agglomerative promotion(AP)and stable improvement(SIm)villages,as well as between characteristic protection(CP)and prospering frontier and enriching people(PE)villages.The factors affecting their distribution include terrain undulation,the percentage of arable land,the distance to the county town,road network density,population density,gross domestic product(GDP),and industrial enterprise density.The influencing factors for the distribution of village types are closely related to the function of each village.Based on the differences in the spatial distribution and influencing factors of different village types,policy suggestions are given for classified development.

A review of dielectric optical metasurfaces for spatial differentiation and edge detection

Dielectric metasurfaces-based planar optical spatial differentiator and edge detection have recently been proposed to play an important role in the parallel and fast image processing technology.With the development of dielectric metasurfaces of different geometries and resonance mechanisms,diverse on-chip spatial differentiators have been proposed by tailoring the dispersion characteristics of subwavelength structures.This review focuses on the basic principles and characteristic parameters of dielectric metasurfaces as first-and second-order spatial differentiators realized via the Green's function approach.The spatial bandwidth and polarization dependence are emphasized as key properties by comparing the optical transfer flinctions of metasurfaces for different incident wavevectors and polarizations.To present the operational capabilities of a two-dimensional spatial differentiator in image information acquisition,edge detection is described to illustrate the practicability of the device.As an application example,experimental demonstrations of edge detection for different biological cells and a flower mold are discussed,in which a spatial differentiator and objective lens or camera are integrated in three optical pathway configurations.The realization of spatial differentiators and edge detection with dielectric metasurfaces provides new opportunities for ultrafast information identification in biological imaging and machine vision.