This paper summarizes a few spatial statistical analysis methods for to measuring spatial autocorrelation and spatial association, discusses the criteria for the identification of spatial association by the use of glo...This paper summarizes a few spatial statistical analysis methods for to measuring spatial autocorrelation and spatial association, discusses the criteria for the identification of spatial association by the use of global Moran Coefficient, Local Moran and Local Geary. Furthermore, a user-friendly statistical module, combining spatial statistical analysis methods with GIS visual techniques, is developed in Arcview using Avenue. An example is also given to show the usefulness of this module in identifying and quantifying the underlying spatial association patterns between economic units.展开更多
After 30 years of economic development, the high-tech industry has played </span><span style="font-family:Verdana;">an </span><span style="font-family:Verdana;">important ro...After 30 years of economic development, the high-tech industry has played </span><span style="font-family:Verdana;">an </span><span style="font-family:Verdana;">important role in China’s national economy. The development of high-level</span><span style="font-family:"font-size:10pt;"> </span><span style="font-family:Verdana;">technological industry plays a leading role in guiding the transformation of </span><span style="font-family:Verdana;">China’s economy from “investment-driven” to “technology-driven”. The</span><span style="font-family:Verdana;"> high-tech industry represents the future industrial development direction and plays a positive role in promoting the transformation of traditional industries. The rapid development of high-tech industry is the key to social progress. In this paper, the traditional analytical model of statistics is combined with principal component analysis and spatial analysis, and R language is used to express the analytical results intuitively on the map. Finally, a comprehensive evaluation is established.展开更多
This paper surveys the current state of teaching spatial statistics in the United States(US),with commentary about the future teaching of such a course.It begins with a historical overview,and proposes what constitute...This paper surveys the current state of teaching spatial statistics in the United States(US),with commentary about the future teaching of such a course.It begins with a historical overview,and proposes what constitutes suitable content for a contemporary spatial statistics course.It notes that contemporary university-level spatial statistics courses are mostly taught across myriad units,including biology/ecology,climatology,economics(as spatial econometrics),environmental studies,epidemiology/public health,forestry,geography,geosciences/earth sciences,geospatial information sciences,mathematics,quantitative social science,soil science,and statistics.It discusses the diffusion of this course across the US,which began in the mid-1980s.One result it reports is a model spatial statistics course offering.展开更多
The relationship between fractal point pattern modeling and statistical methods of pa- rameter estimation in point-process modeling is reviewed. Statistical estimation of the cluster fractal dimension by using Ripley...The relationship between fractal point pattern modeling and statistical methods of pa- rameter estimation in point-process modeling is reviewed. Statistical estimation of the cluster fractal dimension by using Ripley's K-function has advantages in comparison with the more commonly used methods of box-counting and cluster fractal dimension estimation because it corrects for edge effects, not only for rectangular study areas but also for study areas with curved boundaries determined by re- gional geology. Application of box-counting to estimate the fractal dimension of point patterns has the disadvantage that, in general, it is subject to relatively strong "roll-off" effects for smaller boxes. Point patterns used for example in this paper are mainly for gold deposits in the Abitibi volcanic belt on the Canadian Shield. Additionally, it is proposed that, worldwide, the local point patterns of podiform Cr, volcanogenic massive sulphide and porphyry copper deposits, which are spatially distributed within irregularly shaped favorable tracts, satisfy the fractal clustering model with similar fractal dimensions. The problem of deposit size (metal tonnage) is also considered. Several examples are provided of cases in which the Pareto distribution provides good results for the largest deposits in metal size-frequency distribution modeling.展开更多
With the incorporation of spatial statistic method, this paper constructs a state-space model of housing market bubbles, discussing the spatial pattern of housing market bubbles in China,and identifying the dynamic ev...With the incorporation of spatial statistic method, this paper constructs a state-space model of housing market bubbles, discussing the spatial pattern of housing market bubbles in China,and identifying the dynamic evolution process. The results show that: The bubbles of housing market walked along a path from low level to high level and then downsized to a low level during the period of 2009 and 2014, and the highest level stayed at 2011. From overall, the level of housing market bubbles had shown significant spatial autocorrelation and spatial agglomeration. In detail, the direction of North-South in China showed the inverted U shape, i.e., Central region was with high bubbles, and two ends contained low bubbles; from East-West direction, the East had high bubbles and the West contained comparatively low bubbles. Local spatial test indicates that there were some approximate spatial features in housing market bubbles among the adjacent regions. Observed from the level of housing market bubbles, China contained 3 plates: The first was the plate with low bubble level,including 3 provinces in North-East China(provinces of Jilin, Heilongjiang and Liaoning were included,but Dalian in Liaoning province was excluded; the second was the Central and West plate(the provinces of Yunnan, Guizhou, Sichuan, Guangdong, Guangxi, Hunan, Hubei, Gansu, Fujian, Jiangxi and Hainan were included in this plate), which was also featured with low bubble; and the third was Central East plate(provinces or provincial regions of Beijing, Tianjin, Hebei, Jiangsu, Zhejiang, Shanghai, Shandong,Anhui, Shanxi, Shaanxi and Inner Mongolia were included), which was characterized as high bubble region.展开更多
Drug overdose is the leading cause of death by injury in the United States.The incidence of substance use disorder(SUD)in the United States has increased steadily over the past two decades,becoming a major public heal...Drug overdose is the leading cause of death by injury in the United States.The incidence of substance use disorder(SUD)in the United States has increased steadily over the past two decades,becoming a major public health problem for the country.The drivers of the SUD epidemic in the United States have changed over time,characterized by an initial heroin outbreak between 1970 and 1999,followed by a painkiller outbreak,and finally by an ongoing synthetic opioid outbreak.The nature and sources of these abused substances reveal striking differences in the socioeconomic and behavioral factors that shape the drug epidemic.Moreover,the geospatial distribution of the SUD epidemic is not homogeneous.The United States has specific locations where vulnerable communities at high risk of SUD are concentrated,reaffirming the multifactorial socioeconomic nature of this epidemic.A better understanding of the SUD epidemic under a spatial epidemiology framework is necessary to determine the factors that have shaped its spread and how these patterns can be used to predict new outbreaks and create effective mitigation policies.This narrative minireview summarizes the current records of the spatial distribution of the SUD epidemic in the United States across different periods,revealing some spatiotemporal patterns that have preceded the occurrence of outbreaks.By analyzing the epidemic of SUD-related deaths,we also describe the epidemic behavior in areas with high incidence of cases.Finally,we describe public health interventions that can be effective for demographic groups,and we discuss future challenges in the study and control of the SUD epidemic in the country.展开更多
On the basis of the arctic monthly mean sea ice extent data set during 1953-1984, the arctic region is divided into eight subregions,and the analyses of empirical orthogonal functions, power spectrum and maximum entro...On the basis of the arctic monthly mean sea ice extent data set during 1953-1984, the arctic region is divided into eight subregions,and the analyses of empirical orthogonal functions, power spectrum and maximum entropy spectrum are made to indentify the major spatial and temporal features of the sea ice fluctuations within 32-year period. And then, a brief appropriate physical explanation is tentatively suggested. The results show that both seasonal and non-seasonal variations of the sea ice extent are remarkable, and iis mean annual peripheral positions as well as their interannu-al shifting amplitudes are quite different among all subregions. These features are primarily affected by solar radiation, o-cean circulation, sea surface temperature and maritime-continental contrast, while the non-seasonal variations are most possibly affected by the cosmic-geophysical factors such as earth pole shife, earth rotation oscillation and solar activity.展开更多
Using GIS spatial statistical analysis method, with ArcGIS software as an analysis tool, taking the diseased maize in Hedong District of Linyi City as the study object, the distribution characteristic of the diseased ...Using GIS spatial statistical analysis method, with ArcGIS software as an analysis tool, taking the diseased maize in Hedong District of Linyi City as the study object, the distribution characteristic of the diseased crops this time in spatial location was analyzed. The results showed that the diseased crops mainly dis- tributed along with river tributaries and downstream of main rivers. The correlation between adjacent diseased plots was little, so the infection of pests and diseases were excluded, and the major reason of incidence might be river pollution.展开更多
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 ...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.展开更多
Diabetes mellitus(DM)is a growing epidemic with global proportions.It is estimated that in 2019,463 million adults aged 20-79 years were living with DM.The latest evidence shows that DM continues to be a significant g...Diabetes mellitus(DM)is a growing epidemic with global proportions.It is estimated that in 2019,463 million adults aged 20-79 years were living with DM.The latest evidence shows that DM continues to be a significant global health challenge and is likely to continue to grow substantially in the next decades,which would have major implications for healthcare expenditures,particularly in developing countries.Hence,new conceptual and methodological approaches to tackle the epidemic are long overdue.Spatial epidemiology has been a successful approach to control infectious disease epidemics like malaria and human immunodeficiency virus.The implementation of this approach has been expanded to include the study of non-communicable diseases like cancer and cardiovascular diseases.In this review,we discussed the implementation and use of spatial epidemiology and Geographic Information Systems to the study of DM.We reviewed several spatial methods used to understand the spatial structure of the disease and identify the potential geographical drivers of the spatial distribution of DM.Finally,we discussed the use of spatial epidemiology on the design and implementation of geographically targeted prevention and treatment interventions against DM.展开更多
Maintaining a land base that supports safe and realistic training operations is a significant challenge for military land managers which can be informed by frequent monitoring of land condition in relation to manageme...Maintaining a land base that supports safe and realistic training operations is a significant challenge for military land managers which can be informed by frequent monitoring of land condition in relation to management practices. This study explores the relationship between fire and trends in tallgrass prairie vegetation at military and non-military sites in the Kansas Flint Hills. The response variable was the long-term linear trend (2001-2010) of surface greenness measured by MODIS NDVI using BFAST time series trend analysis. Explanatory variables included fire regime (frequency and seasonality) and spatial strata based on existing management unit boundaries. Several non-spatial generalized linear models (GLM) were computed to explain trends by fire regime and/or stratification. Spatialized versions of the GLMs were also constructed. For non-spatial models at the military site, fire regime explained little (4%) of the observed surface greenness trend compared to strata alone (7% - 26%). The non-spatial and spatial models for the non-military site performed better for each explanatory variable and combination tested with fire regime. Existing stratifications contained much of the spatial structure in model residuals. Fire had only a marginal effect on surface greenness trends at the military site despite the use of burning as a grassland management tool. Interestingly, fire explained more of the trend at the non-military site and models including strata improved explanatory power. Analysis of spatial model predictors based on management unit stratification suggested ways to reduce the number of strata while achieving similar performance and may benefit managers of other public areas lacking sound data regarding land usage.展开更多
In this study,microstructural brain damage in Parkinson's disease patients was examined using diffusion tensor imaging and tract-based spatial statistics.The analyses revealed the presence of neuronal damage in the s...In this study,microstructural brain damage in Parkinson's disease patients was examined using diffusion tensor imaging and tract-based spatial statistics.The analyses revealed the presence of neuronal damage in the substantia nigra and putamen in the Parkinson's disease patients.Moreover,disease symptoms worsened with increasing damage to the substantia nigra,confirming that the substantia nigra and basal ganglia are the main structures affected in Parkinson's disease.We also found that microstructural damage to the putamen,caudate nucleus and frontal lobe positively correlated with depression.Based on the tract-based spatial statistics,various white matter tracts appeared to have microstructural damage,and this correlated with cognitive disorder and depression.Taken together,our results suggest that diffusion tensor imaging and tract-based spatial statistics can be used to effectively study brain function and microstructural changes in patients with Parkinson's disease.Our novel findings should contribute to our understanding of the histopathological basis of cognitive dysfunction and depression in Parkinson's disease.展开更多
We observed the characteristics of white matter fibers and gray matter in multiple sclerosis patients, to identify changes in diffusion tensor imaging fractional anisotropy values following white matter fiber injury. ...We observed the characteristics of white matter fibers and gray matter in multiple sclerosis patients, to identify changes in diffusion tensor imaging fractional anisotropy values following white matter fiber injury. We analyzed the correlation between fractional anisotropy values and changes in whole-brain gray matter volume. The participants included 20 patients with relapsing-remitting multiple sclerosis and 20 healthy volunteers as controls. All subjects underwent head magnetic resonance imaging and diffusion tensor imaging. Our results revealed that fractional anisotropy values decreased and gray matter volumes were reduced in the genu and splenium of corpus callosum, left anterior thalamic radiation, hippocampus, uncinate fasciculus, right corticospinal tract, bilateral cingulate gyri, and inferior longitudinal fasciculus in multiple sclerosis patients. Gray matter volumes were significantly different between the two groups in the right frontal lobe(superior frontal, middle frontal, precentral, and orbital gyri), right parietal lobe(postcentral and inferior parietal gyri), right temporal lobe(caudate nucleus), right occipital lobe(middle occipital gyrus), right insula, right parahippocampal gyrus, and left cingulate gyrus. The voxel sizes of atrophic gray matter positively correlated with fractional anisotropy values in white matter association fibers in the patient group. These findings suggest that white matter fiber bundles are extensively injured in multiple sclerosis patients. The main areas of gray matter atrophy in multiple sclerosis are the frontal lobe, parietal lobe, caudate nucleus, parahippocampal gyrus, and cingulate gyrus. Gray matter atrophy is strongly associated with white matter injury in multiple sclerosis patients, particularly with injury to association fibers.展开更多
Land use intensity is a valuable concept to understand integrated land use system, which is unlike the traditional approach of analysis that often examines one or a few aspects of land use disregarding multidimensiona...Land use intensity is a valuable concept to understand integrated land use system, which is unlike the traditional approach of analysis that often examines one or a few aspects of land use disregarding multidimensionality of the intensification process in the complex land system. Land use intensity is based on an integrative conceptual framework focusing on both inputs to and outputs from the land. Geographers’ non-stationary data-analysis technique is very suitable for most of the spatial data analysis. Our study was carried out in the northeast part of the Andhikhola watershed lying in the Middle Hills of Nepal, where over the last two decades, heavy loss of labor due to outmigration of rural farmers and increasing urbanization in the relatively easy accessible lowland areas has caused agricultural land abandonment. Our intention in this study was to ascertain factors of spatial pattern of intensity dynamism between human and nature relationships in the integrated traditional agricultural system. High resolution aerial photo and multispectral satellite image were used to derive data on land use and land cover. In addition, field verification, information collected from the field and census report were other data sources. Explanatory variables were derived from those digital and analogue data. Ordinary Least Square(OLS) technique was used for filtering of the variables. Geographically Weighted Regression(GWR) model was used to identify major determining factors of land use intensity dynamics. Moran’s I technique was used for model validation. GWR model was executed to identify the strength of explanatory variables explaining change of land use intensity. Accordingly, 10 variables were identified having the greatest strength to explain land use intensity change in the study area, of which physical variables such as slope gradient, temperature and solar radiation revealed the highest strength followed by variables of accessibility and natural resource. Depopulation in recent decades has been a major driver of land use intensity change but spatial variability of land use intensity was highly controlled by physical suitability, accessibility and availability of natural resources.展开更多
Gully erosion is a worldwide problem of land degradation and water quality,and it is also frequent in Brazil.Typically,anthropic influence is the major driver of gully evolution.To study and monitor gullies it is nece...Gully erosion is a worldwide problem of land degradation and water quality,and it is also frequent in Brazil.Typically,anthropic influence is the major driver of gully evolution.To study and monitor gullies it is necessary to use specific instruments and methods to obtain accurate information.The objective of this study was to use Terrestrial Laser Scanning(TLS) to create digital elevation model(DEM) accurately and define morphometric variables that characterize gullies in a mountainous relief.Two different interpolations were evaluated using the Topogrid and GridSurfaceCreate algorithms to elaborate DEM.Topographic profile for gullies was used to assess modeling quality.The DEM of the Gully 1(G1) from the Topogrid algorithm estimated soil loss of 49%,whereas the GridSurfaceCreate algorithm estimated a soil loss of97%,in a period of 1 year.The estimated soil loss for the Gully 2(G2) was 14% from the Topogrid,and 8%from the GridSurfaceCreate algorithm.The GridSurfaceCreate algorithm underestimated the volume to area ratio for G2 due to a failure on interpolating a region of low point representativity.The Topogrid algorithm represented better the terrain irregularities,as observed through the topographic profiles traced in three regions of G1 and G2.Statistical analysis showed that the GridSurfaceCreate algorithm presented lower accuracy in estimating elevations.The underestimation trend of this algorithm was also observed in G2.The gullies showed considerable soil losses,which may reduce the areas suitable for agricultural activities,and silting up of water courses.The Topogrid algorithm presented satisfactory results,denoting great potential to produce morphometric data of gullies.展开更多
<p> <span style="font-family:;" "="">The Ugandan economy is largely dependent on rural-based and rain-fed agriculture. This creates a critical need to understand the rainfall dynam...<p> <span style="font-family:;" "="">The Ugandan economy is largely dependent on rural-based and rain-fed agriculture. This creates a critical need to understand the rainfall dynamics at the local scale. However, the country has a sternly sparse and unreliable rain gauge network. This research, therefore, set</span><span style="font-family:;" "="">s</span><span style="font-family:;" "=""> out to evaluate the use of </span><span style="font-family:;" "="">the </span><span style="font-family:;" "="">CHIRPS satellite gridded dataset as an alternative rainfall estimate for local modelling of rainfall in Uganda. Complete, continuous and reliable <i>in</i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:;" "="">situ</span></i><span style="font-family:;" "=""> station observations for the period between 2012 and 2020 were used for the comparison with CHIRPS satellite data models in the same epoch. Rainfall values within the minimum 5 km and maximum 20 km radii</span><span style="font-family:;" "=""> </span><span style="font-family:;" "="">from the <i>in</i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:;" "="">situ</span></i><span style="font-family:;" "=""> stations were extracted at a 5 km interval from the interpolated <i>in</i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:;" "="">situ</span></i><span style="font-family:;" "=""> station surface and the CHIRPS satellite data model for comparison. Results of the 5 km radius were adopted for the evaluation as it</span><span style="font-family:;" "="">’</span><span style="font-family:;" "="">s closer to the optimal rain gauge coverage of 25 km<sup>2</sup>. They show the R<sup>2</sup> = 0.91, NSE = 0.88, PBias = <span style="white-space:nowrap;"><span style="white-space:nowrap;">-</span></span>0.24 and RSR = 0.35. This attests that the CHIRPS satellite gridded datasets provide a good approximation and simulation of <i>in</i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:;" "="">situ</span></i><span style="font-family:;" "=""> station data with high collinearity and minimum deviation. This tallies with related studies in other regions that have found CHIRPS datasets superior to interpolation surfaces and sparse rain gauge data in the comprehensive estimation of rainfall. With a 0.05<span style="white-space:nowrap;">°</span> * 0.05<span style="white-space:nowrap;">°</span> (Latitude, longitude) spatial resolution, CHIRPS satellite gridded rainfall estimates are therefore able to provide a comprehensive rainfall estimation at a local scale. Essentially these results reward research science in regions like Uganda that have sparse rain gauges networks characterized by incomplete, inconsistent and unreliable data with an empirically researched alternative source of rainfall estimation data. It further provides a platform to scientifically interrogate the rainfall dynamics at a local scale in order to infuse local policy with evidence-based formulation and application.</span><span></span> </p>展开更多
To study the water quality influenced by the anthropogenic activities and its impact on the phytoplankton diversity in the surface waters of Miaodao Archipelago, the spatiotemporal variations in phytoplankton communit...To study the water quality influenced by the anthropogenic activities and its impact on the phytoplankton diversity in the surface waters of Miaodao Archipelago, the spatiotemporal variations in phytoplankton communities and the environmental properties of the surface waters surrounding the Five Southern Islands of Miaodao Archipelago were investigated, based on seasonal field survey conducted from November 2012 to August 2013. During the survey, a total of 109 phytoplankton species from 3 groups were identified in the southern waters of Miaodao Archipelago, of which 77 were diatoms, 29 were dinoflagellates, and 3 were chrysophytes. Species number was higher in winter(73), moderate in autumn(70), but lower in summer(31) and spring(27). The species richness index in autumn(5.92) and winter(4.28) was higher than that in summer(2.83) and spring(1.41).The Shannon-Wiener diversity index was high in autumn(2.82), followed by winter(1.99) and summer(1.92), and low in spring(0.07). The species evenness index in autumn(0.46) and summer(0.39) was higher than that in winter(0.32) and spring(0.02). On the basis of principal component analysis(PCA) and redundancy analysis(RDA), we found that dissolved inorganic nitrogen(DIN) and chemical oxygen demand(COD) in spring, COD in summer, p H in autumn, and salinity and oil pollutant in winter, respectively, showed the strongest association with the distribution of phytoplankton diversity. The spatial heterogeneity of the southern waters of Miaodao Archipelago was quite obvious, and three zones, i.e., northeastern, southwestern and inter-island water area, were identified by cluster analysis(CA) based on key environmental variables.展开更多
Habitat quality assessments are of great significance for protecting biodiversity.This study analyzes the changing habitat quality of Lashihai watershed based on SPOT satellite images.We extracted the land use data fo...Habitat quality assessments are of great significance for protecting biodiversity.This study analyzes the changing habitat quality of Lashihai watershed based on SPOT satellite images.We extracted the land use data for Lashihai watershed in Yunnan province for the years 2000 and 2015,and then used an INVEST model to evaluate habitat degradation,habitat quality and habitat scarcity in the study area from 2000 to 2015.Spatial statistical methods were used to determine changes to spatial dynamics.Results indicate that the number of areas with habitat degradation was generally small,and that both the number of areas with habitat degradation and the degree of degradation had fallen noticeably during the fifteen-year study period.In general,the quality of habitats was main- tained or improved,while the quality of habitats decreased in only a few areas.The scarcity of habitats for cultivated land had increased,the tension between people and land use was relatively prominent.The reason habitat quality in Lashihai watershed has improved can be attributed to three factors:1)The policy of returning farmland to forests since 2000 has been well implemented and has achieved remarkable results.Loss of forests from logging and deforestation has basically been eliminated,and great progress has been made restoring the ecological environment.2)High background value of quality habitat suitability benefits from the research area's high vegetation coverage.3)The development of the local tourism economy has transformed the area's ecological advantages into an economic bonus,greatly increasing the income level and living standards of residents.At the same time,the ecological resource bonus has increased the enthusiasm of residents for ecological protection and has helped to promote the protection of local eco-systems,both reducing ecological degradation and improving habitat quality.At the same time,increasing conflicts between land and people should be addressed.Support is needed to promote development of the ecological economy while continuously reducing ecological degradation and further increasing residents'income.There must be less reliance on industry and less pressure on both land and people,all the while ensuring that the local economy and ecology can more forward together in a sustainable way.展开更多
Measuring the relative importance and assigning weights to conditioning factors of land- slides occurrence are significant for landslide prevention and/or mitigation. In this contribution, a fractal method is introduc...Measuring the relative importance and assigning weights to conditioning factors of land- slides occurrence are significant for landslide prevention and/or mitigation. In this contribution, a fractal method is introduced for measuring the spatial relationships between landslides and condition- ing factors (such as faults, rivers, geological boundaries, and roads), and for assigning weights to condi- tioning factors for mapping of landslide susceptibility. This method can be expressed as p=C~, where d is the fractal dimension, and C is a constant. This relationship indicates a fractal relation between land- slide density (p) and distances to conditioning factors (6). The case of d〉0 suggests a significant spatial correlation between landslides and conditioning factors. The larger the d (〉0) value, the stronger the spatial correlation is between landslides and a specific conditioning factor. Two case studies in South China were examined to demonstrate the usefulness of this novel method.展开更多
The selection of discretization criteria and interval numbers of landslide-related environmental factors generally fails to quantitatively determine orfilter,resulting in uncertainties and limitations in the performan...The selection of discretization criteria and interval numbers of landslide-related environmental factors generally fails to quantitatively determine orfilter,resulting in uncertainties and limitations in the performance of machine learning(ML)methods for landslide susceptibility mapping(LSM).The aim of this study is to propose a robust discretization criterion(RDC)to quantify and explore the uncertainty and subjectivity of different discretization methods.The RDC consists of two steps:raw classification dataset generation and optimal dataset extraction.To evaluate the robustness of the proposed RDC method,Lushan County of Sichuan Province in China was chosen as the study area to generate the LSM based on three datasets(optimal dataset,original dataset with continuous values,and statistical dataset)using three popular ML methods,namely,convolution neural network,random forest,and logistic regression.The results show that the areas under the receiver operating characteristic curve(AUCs)of the optimal dataset for the abovementioned ML models are 0.963,0.961,and 0.930 which are higher than those of the original dataset(0.938,0.947,and 0.900)and statistical dataset(0.948,0.954,and 0.897).In conclusion,the RDC method can extract the more representative features from environmental factors and outperform the other conventional discretization methods.展开更多
文摘This paper summarizes a few spatial statistical analysis methods for to measuring spatial autocorrelation and spatial association, discusses the criteria for the identification of spatial association by the use of global Moran Coefficient, Local Moran and Local Geary. Furthermore, a user-friendly statistical module, combining spatial statistical analysis methods with GIS visual techniques, is developed in Arcview using Avenue. An example is also given to show the usefulness of this module in identifying and quantifying the underlying spatial association patterns between economic units.
文摘After 30 years of economic development, the high-tech industry has played </span><span style="font-family:Verdana;">an </span><span style="font-family:Verdana;">important role in China’s national economy. The development of high-level</span><span style="font-family:"font-size:10pt;"> </span><span style="font-family:Verdana;">technological industry plays a leading role in guiding the transformation of </span><span style="font-family:Verdana;">China’s economy from “investment-driven” to “technology-driven”. The</span><span style="font-family:Verdana;"> high-tech industry represents the future industrial development direction and plays a positive role in promoting the transformation of traditional industries. The rapid development of high-tech industry is the key to social progress. In this paper, the traditional analytical model of statistics is combined with principal component analysis and spatial analysis, and R language is used to express the analytical results intuitively on the map. Finally, a comprehensive evaluation is established.
文摘This paper surveys the current state of teaching spatial statistics in the United States(US),with commentary about the future teaching of such a course.It begins with a historical overview,and proposes what constitutes suitable content for a contemporary spatial statistics course.It notes that contemporary university-level spatial statistics courses are mostly taught across myriad units,including biology/ecology,climatology,economics(as spatial econometrics),environmental studies,epidemiology/public health,forestry,geography,geosciences/earth sciences,geospatial information sciences,mathematics,quantitative social science,soil science,and statistics.It discusses the diffusion of this course across the US,which began in the mid-1980s.One result it reports is a model spatial statistics course offering.
基金supported by Geological Survey of Canada and China University of Geosciences (Wuhan)
文摘The relationship between fractal point pattern modeling and statistical methods of pa- rameter estimation in point-process modeling is reviewed. Statistical estimation of the cluster fractal dimension by using Ripley's K-function has advantages in comparison with the more commonly used methods of box-counting and cluster fractal dimension estimation because it corrects for edge effects, not only for rectangular study areas but also for study areas with curved boundaries determined by re- gional geology. Application of box-counting to estimate the fractal dimension of point patterns has the disadvantage that, in general, it is subject to relatively strong "roll-off" effects for smaller boxes. Point patterns used for example in this paper are mainly for gold deposits in the Abitibi volcanic belt on the Canadian Shield. Additionally, it is proposed that, worldwide, the local point patterns of podiform Cr, volcanogenic massive sulphide and porphyry copper deposits, which are spatially distributed within irregularly shaped favorable tracts, satisfy the fractal clustering model with similar fractal dimensions. The problem of deposit size (metal tonnage) is also considered. Several examples are provided of cases in which the Pareto distribution provides good results for the largest deposits in metal size-frequency distribution modeling.
基金Supported by the China Scholarship Council,the Natural Science Foundation of Hunan(2017JJ3010)the Science Foundation for the Excellent Youth Scholars of Department of Education of Hunan(13B008)
文摘With the incorporation of spatial statistic method, this paper constructs a state-space model of housing market bubbles, discussing the spatial pattern of housing market bubbles in China,and identifying the dynamic evolution process. The results show that: The bubbles of housing market walked along a path from low level to high level and then downsized to a low level during the period of 2009 and 2014, and the highest level stayed at 2011. From overall, the level of housing market bubbles had shown significant spatial autocorrelation and spatial agglomeration. In detail, the direction of North-South in China showed the inverted U shape, i.e., Central region was with high bubbles, and two ends contained low bubbles; from East-West direction, the East had high bubbles and the West contained comparatively low bubbles. Local spatial test indicates that there were some approximate spatial features in housing market bubbles among the adjacent regions. Observed from the level of housing market bubbles, China contained 3 plates: The first was the plate with low bubble level,including 3 provinces in North-East China(provinces of Jilin, Heilongjiang and Liaoning were included,but Dalian in Liaoning province was excluded; the second was the Central and West plate(the provinces of Yunnan, Guizhou, Sichuan, Guangdong, Guangxi, Hunan, Hubei, Gansu, Fujian, Jiangxi and Hainan were included in this plate), which was also featured with low bubble; and the third was Central East plate(provinces or provincial regions of Beijing, Tianjin, Hebei, Jiangsu, Zhejiang, Shanghai, Shandong,Anhui, Shanxi, Shaanxi and Inner Mongolia were included), which was characterized as high bubble region.
文摘Drug overdose is the leading cause of death by injury in the United States.The incidence of substance use disorder(SUD)in the United States has increased steadily over the past two decades,becoming a major public health problem for the country.The drivers of the SUD epidemic in the United States have changed over time,characterized by an initial heroin outbreak between 1970 and 1999,followed by a painkiller outbreak,and finally by an ongoing synthetic opioid outbreak.The nature and sources of these abused substances reveal striking differences in the socioeconomic and behavioral factors that shape the drug epidemic.Moreover,the geospatial distribution of the SUD epidemic is not homogeneous.The United States has specific locations where vulnerable communities at high risk of SUD are concentrated,reaffirming the multifactorial socioeconomic nature of this epidemic.A better understanding of the SUD epidemic under a spatial epidemiology framework is necessary to determine the factors that have shaped its spread and how these patterns can be used to predict new outbreaks and create effective mitigation policies.This narrative minireview summarizes the current records of the spatial distribution of the SUD epidemic in the United States across different periods,revealing some spatiotemporal patterns that have preceded the occurrence of outbreaks.By analyzing the epidemic of SUD-related deaths,we also describe the epidemic behavior in areas with high incidence of cases.Finally,we describe public health interventions that can be effective for demographic groups,and we discuss future challenges in the study and control of the SUD epidemic in the country.
文摘On the basis of the arctic monthly mean sea ice extent data set during 1953-1984, the arctic region is divided into eight subregions,and the analyses of empirical orthogonal functions, power spectrum and maximum entropy spectrum are made to indentify the major spatial and temporal features of the sea ice fluctuations within 32-year period. And then, a brief appropriate physical explanation is tentatively suggested. The results show that both seasonal and non-seasonal variations of the sea ice extent are remarkable, and iis mean annual peripheral positions as well as their interannu-al shifting amplitudes are quite different among all subregions. These features are primarily affected by solar radiation, o-cean circulation, sea surface temperature and maritime-continental contrast, while the non-seasonal variations are most possibly affected by the cosmic-geophysical factors such as earth pole shife, earth rotation oscillation and solar activity.
文摘Using GIS spatial statistical analysis method, with ArcGIS software as an analysis tool, taking the diseased maize in Hedong District of Linyi City as the study object, the distribution characteristic of the diseased crops this time in spatial location was analyzed. The results showed that the diseased crops mainly dis- tributed along with river tributaries and downstream of main rivers. The correlation between adjacent diseased plots was little, so the infection of pests and diseases were excluded, and the major reason of incidence might be river pollution.
基金National Natural Science Foundation of China, No.40701150 National Science and Technology Support Project, No.07H70163AR National Key Project of Scientific and Technical Supporting Programs,No.2006BAC08B03,No.2008BAC34B06
文摘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.
文摘Diabetes mellitus(DM)is a growing epidemic with global proportions.It is estimated that in 2019,463 million adults aged 20-79 years were living with DM.The latest evidence shows that DM continues to be a significant global health challenge and is likely to continue to grow substantially in the next decades,which would have major implications for healthcare expenditures,particularly in developing countries.Hence,new conceptual and methodological approaches to tackle the epidemic are long overdue.Spatial epidemiology has been a successful approach to control infectious disease epidemics like malaria and human immunodeficiency virus.The implementation of this approach has been expanded to include the study of non-communicable diseases like cancer and cardiovascular diseases.In this review,we discussed the implementation and use of spatial epidemiology and Geographic Information Systems to the study of DM.We reviewed several spatial methods used to understand the spatial structure of the disease and identify the potential geographical drivers of the spatial distribution of DM.Finally,we discussed the use of spatial epidemiology on the design and implementation of geographically targeted prevention and treatment interventions against DM.
文摘Maintaining a land base that supports safe and realistic training operations is a significant challenge for military land managers which can be informed by frequent monitoring of land condition in relation to management practices. This study explores the relationship between fire and trends in tallgrass prairie vegetation at military and non-military sites in the Kansas Flint Hills. The response variable was the long-term linear trend (2001-2010) of surface greenness measured by MODIS NDVI using BFAST time series trend analysis. Explanatory variables included fire regime (frequency and seasonality) and spatial strata based on existing management unit boundaries. Several non-spatial generalized linear models (GLM) were computed to explain trends by fire regime and/or stratification. Spatialized versions of the GLMs were also constructed. For non-spatial models at the military site, fire regime explained little (4%) of the observed surface greenness trend compared to strata alone (7% - 26%). The non-spatial and spatial models for the non-military site performed better for each explanatory variable and combination tested with fire regime. Existing stratifications contained much of the spatial structure in model residuals. Fire had only a marginal effect on surface greenness trends at the military site despite the use of burning as a grassland management tool. Interestingly, fire explained more of the trend at the non-military site and models including strata improved explanatory power. Analysis of spatial model predictors based on management unit stratification suggested ways to reduce the number of strata while achieving similar performance and may benefit managers of other public areas lacking sound data regarding land usage.
文摘In this study,microstructural brain damage in Parkinson's disease patients was examined using diffusion tensor imaging and tract-based spatial statistics.The analyses revealed the presence of neuronal damage in the substantia nigra and putamen in the Parkinson's disease patients.Moreover,disease symptoms worsened with increasing damage to the substantia nigra,confirming that the substantia nigra and basal ganglia are the main structures affected in Parkinson's disease.We also found that microstructural damage to the putamen,caudate nucleus and frontal lobe positively correlated with depression.Based on the tract-based spatial statistics,various white matter tracts appeared to have microstructural damage,and this correlated with cognitive disorder and depression.Taken together,our results suggest that diffusion tensor imaging and tract-based spatial statistics can be used to effectively study brain function and microstructural changes in patients with Parkinson's disease.Our novel findings should contribute to our understanding of the histopathological basis of cognitive dysfunction and depression in Parkinson's disease.
基金supported by the Project of Science and Technology Department of Jilin Province in China,No.20160101023JC
文摘We observed the characteristics of white matter fibers and gray matter in multiple sclerosis patients, to identify changes in diffusion tensor imaging fractional anisotropy values following white matter fiber injury. We analyzed the correlation between fractional anisotropy values and changes in whole-brain gray matter volume. The participants included 20 patients with relapsing-remitting multiple sclerosis and 20 healthy volunteers as controls. All subjects underwent head magnetic resonance imaging and diffusion tensor imaging. Our results revealed that fractional anisotropy values decreased and gray matter volumes were reduced in the genu and splenium of corpus callosum, left anterior thalamic radiation, hippocampus, uncinate fasciculus, right corticospinal tract, bilateral cingulate gyri, and inferior longitudinal fasciculus in multiple sclerosis patients. Gray matter volumes were significantly different between the two groups in the right frontal lobe(superior frontal, middle frontal, precentral, and orbital gyri), right parietal lobe(postcentral and inferior parietal gyri), right temporal lobe(caudate nucleus), right occipital lobe(middle occipital gyrus), right insula, right parahippocampal gyrus, and left cingulate gyrus. The voxel sizes of atrophic gray matter positively correlated with fractional anisotropy values in white matter association fibers in the patient group. These findings suggest that white matter fiber bundles are extensively injured in multiple sclerosis patients. The main areas of gray matter atrophy in multiple sclerosis are the frontal lobe, parietal lobe, caudate nucleus, parahippocampal gyrus, and cingulate gyrus. Gray matter atrophy is strongly associated with white matter injury in multiple sclerosis patients, particularly with injury to association fibers.
基金This study was financially supported by the CAS Overseas Institutions Platform Project(Grant No.131C11KYSB20200033)。
文摘Land use intensity is a valuable concept to understand integrated land use system, which is unlike the traditional approach of analysis that often examines one or a few aspects of land use disregarding multidimensionality of the intensification process in the complex land system. Land use intensity is based on an integrative conceptual framework focusing on both inputs to and outputs from the land. Geographers’ non-stationary data-analysis technique is very suitable for most of the spatial data analysis. Our study was carried out in the northeast part of the Andhikhola watershed lying in the Middle Hills of Nepal, where over the last two decades, heavy loss of labor due to outmigration of rural farmers and increasing urbanization in the relatively easy accessible lowland areas has caused agricultural land abandonment. Our intention in this study was to ascertain factors of spatial pattern of intensity dynamism between human and nature relationships in the integrated traditional agricultural system. High resolution aerial photo and multispectral satellite image were used to derive data on land use and land cover. In addition, field verification, information collected from the field and census report were other data sources. Explanatory variables were derived from those digital and analogue data. Ordinary Least Square(OLS) technique was used for filtering of the variables. Geographically Weighted Regression(GWR) model was used to identify major determining factors of land use intensity dynamics. Moran’s I technique was used for model validation. GWR model was executed to identify the strength of explanatory variables explaining change of land use intensity. Accordingly, 10 variables were identified having the greatest strength to explain land use intensity change in the study area, of which physical variables such as slope gradient, temperature and solar radiation revealed the highest strength followed by variables of accessibility and natural resource. Depopulation in recent decades has been a major driver of land use intensity change but spatial variability of land use intensity was highly controlled by physical suitability, accessibility and availability of natural resources.
基金the FAPERJ for the concession scholarships for the first author (Grants No. E26/101.897/2010 - 63010)funded by the Pró-Equipamentos program for Capes (Coordenacao de Aperfeicoamento de Pessoal de Nível Superior)。
文摘Gully erosion is a worldwide problem of land degradation and water quality,and it is also frequent in Brazil.Typically,anthropic influence is the major driver of gully evolution.To study and monitor gullies it is necessary to use specific instruments and methods to obtain accurate information.The objective of this study was to use Terrestrial Laser Scanning(TLS) to create digital elevation model(DEM) accurately and define morphometric variables that characterize gullies in a mountainous relief.Two different interpolations were evaluated using the Topogrid and GridSurfaceCreate algorithms to elaborate DEM.Topographic profile for gullies was used to assess modeling quality.The DEM of the Gully 1(G1) from the Topogrid algorithm estimated soil loss of 49%,whereas the GridSurfaceCreate algorithm estimated a soil loss of97%,in a period of 1 year.The estimated soil loss for the Gully 2(G2) was 14% from the Topogrid,and 8%from the GridSurfaceCreate algorithm.The GridSurfaceCreate algorithm underestimated the volume to area ratio for G2 due to a failure on interpolating a region of low point representativity.The Topogrid algorithm represented better the terrain irregularities,as observed through the topographic profiles traced in three regions of G1 and G2.Statistical analysis showed that the GridSurfaceCreate algorithm presented lower accuracy in estimating elevations.The underestimation trend of this algorithm was also observed in G2.The gullies showed considerable soil losses,which may reduce the areas suitable for agricultural activities,and silting up of water courses.The Topogrid algorithm presented satisfactory results,denoting great potential to produce morphometric data of gullies.
文摘<p> <span style="font-family:;" "="">The Ugandan economy is largely dependent on rural-based and rain-fed agriculture. This creates a critical need to understand the rainfall dynamics at the local scale. However, the country has a sternly sparse and unreliable rain gauge network. This research, therefore, set</span><span style="font-family:;" "="">s</span><span style="font-family:;" "=""> out to evaluate the use of </span><span style="font-family:;" "="">the </span><span style="font-family:;" "="">CHIRPS satellite gridded dataset as an alternative rainfall estimate for local modelling of rainfall in Uganda. Complete, continuous and reliable <i>in</i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:;" "="">situ</span></i><span style="font-family:;" "=""> station observations for the period between 2012 and 2020 were used for the comparison with CHIRPS satellite data models in the same epoch. Rainfall values within the minimum 5 km and maximum 20 km radii</span><span style="font-family:;" "=""> </span><span style="font-family:;" "="">from the <i>in</i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:;" "="">situ</span></i><span style="font-family:;" "=""> stations were extracted at a 5 km interval from the interpolated <i>in</i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:;" "="">situ</span></i><span style="font-family:;" "=""> station surface and the CHIRPS satellite data model for comparison. Results of the 5 km radius were adopted for the evaluation as it</span><span style="font-family:;" "="">’</span><span style="font-family:;" "="">s closer to the optimal rain gauge coverage of 25 km<sup>2</sup>. They show the R<sup>2</sup> = 0.91, NSE = 0.88, PBias = <span style="white-space:nowrap;"><span style="white-space:nowrap;">-</span></span>0.24 and RSR = 0.35. This attests that the CHIRPS satellite gridded datasets provide a good approximation and simulation of <i>in</i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:;" "="">situ</span></i><span style="font-family:;" "=""> station data with high collinearity and minimum deviation. This tallies with related studies in other regions that have found CHIRPS datasets superior to interpolation surfaces and sparse rain gauge data in the comprehensive estimation of rainfall. With a 0.05<span style="white-space:nowrap;">°</span> * 0.05<span style="white-space:nowrap;">°</span> (Latitude, longitude) spatial resolution, CHIRPS satellite gridded rainfall estimates are therefore able to provide a comprehensive rainfall estimation at a local scale. Essentially these results reward research science in regions like Uganda that have sparse rain gauges networks characterized by incomplete, inconsistent and unreliable data with an empirically researched alternative source of rainfall estimation data. It further provides a platform to scientifically interrogate the rainfall dynamics at a local scale in order to infuse local policy with evidence-based formulation and application.</span><span></span> </p>
基金The Special Project of Science and Technology Fundamental Work from the Ministry of Science and Technology of China under contract No.2012FY112500the National Natural Science Foundation of China under contract Nos 41206111 and 41206112
文摘To study the water quality influenced by the anthropogenic activities and its impact on the phytoplankton diversity in the surface waters of Miaodao Archipelago, the spatiotemporal variations in phytoplankton communities and the environmental properties of the surface waters surrounding the Five Southern Islands of Miaodao Archipelago were investigated, based on seasonal field survey conducted from November 2012 to August 2013. During the survey, a total of 109 phytoplankton species from 3 groups were identified in the southern waters of Miaodao Archipelago, of which 77 were diatoms, 29 were dinoflagellates, and 3 were chrysophytes. Species number was higher in winter(73), moderate in autumn(70), but lower in summer(31) and spring(27). The species richness index in autumn(5.92) and winter(4.28) was higher than that in summer(2.83) and spring(1.41).The Shannon-Wiener diversity index was high in autumn(2.82), followed by winter(1.99) and summer(1.92), and low in spring(0.07). The species evenness index in autumn(0.46) and summer(0.39) was higher than that in winter(0.32) and spring(0.02). On the basis of principal component analysis(PCA) and redundancy analysis(RDA), we found that dissolved inorganic nitrogen(DIN) and chemical oxygen demand(COD) in spring, COD in summer, p H in autumn, and salinity and oil pollutant in winter, respectively, showed the strongest association with the distribution of phytoplankton diversity. The spatial heterogeneity of the southern waters of Miaodao Archipelago was quite obvious, and three zones, i.e., northeastern, southwestern and inter-island water area, were identified by cluster analysis(CA) based on key environmental variables.
基金Supported by fund for building world-class universities(disciplines) of Renmin University of China(2018)
文摘Habitat quality assessments are of great significance for protecting biodiversity.This study analyzes the changing habitat quality of Lashihai watershed based on SPOT satellite images.We extracted the land use data for Lashihai watershed in Yunnan province for the years 2000 and 2015,and then used an INVEST model to evaluate habitat degradation,habitat quality and habitat scarcity in the study area from 2000 to 2015.Spatial statistical methods were used to determine changes to spatial dynamics.Results indicate that the number of areas with habitat degradation was generally small,and that both the number of areas with habitat degradation and the degree of degradation had fallen noticeably during the fifteen-year study period.In general,the quality of habitats was main- tained or improved,while the quality of habitats decreased in only a few areas.The scarcity of habitats for cultivated land had increased,the tension between people and land use was relatively prominent.The reason habitat quality in Lashihai watershed has improved can be attributed to three factors:1)The policy of returning farmland to forests since 2000 has been well implemented and has achieved remarkable results.Loss of forests from logging and deforestation has basically been eliminated,and great progress has been made restoring the ecological environment.2)High background value of quality habitat suitability benefits from the research area's high vegetation coverage.3)The development of the local tourism economy has transformed the area's ecological advantages into an economic bonus,greatly increasing the income level and living standards of residents.At the same time,the ecological resource bonus has increased the enthusiasm of residents for ecological protection and has helped to promote the protection of local eco-systems,both reducing ecological degradation and improving habitat quality.At the same time,increasing conflicts between land and people should be addressed.Support is needed to promote development of the ecological economy while continuously reducing ecological degradation and further increasing residents'income.There must be less reliance on industry and less pressure on both land and people,all the while ensuring that the local economy and ecology can more forward together in a sustainable way.
基金financial support from the National Natural Science Foundation of China (No. 41522206)the MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (No. MSFGPMR03-3)
文摘Measuring the relative importance and assigning weights to conditioning factors of land- slides occurrence are significant for landslide prevention and/or mitigation. In this contribution, a fractal method is introduced for measuring the spatial relationships between landslides and condition- ing factors (such as faults, rivers, geological boundaries, and roads), and for assigning weights to condi- tioning factors for mapping of landslide susceptibility. This method can be expressed as p=C~, where d is the fractal dimension, and C is a constant. This relationship indicates a fractal relation between land- slide density (p) and distances to conditioning factors (6). The case of d〉0 suggests a significant spatial correlation between landslides and conditioning factors. The larger the d (〉0) value, the stronger the spatial correlation is between landslides and a specific conditioning factor. Two case studies in South China were examined to demonstrate the usefulness of this novel method.
基金This work was supported by Project of Sichuan Science and Technology Program:[Grant Number 2019YFG0187].
文摘The selection of discretization criteria and interval numbers of landslide-related environmental factors generally fails to quantitatively determine orfilter,resulting in uncertainties and limitations in the performance of machine learning(ML)methods for landslide susceptibility mapping(LSM).The aim of this study is to propose a robust discretization criterion(RDC)to quantify and explore the uncertainty and subjectivity of different discretization methods.The RDC consists of two steps:raw classification dataset generation and optimal dataset extraction.To evaluate the robustness of the proposed RDC method,Lushan County of Sichuan Province in China was chosen as the study area to generate the LSM based on three datasets(optimal dataset,original dataset with continuous values,and statistical dataset)using three popular ML methods,namely,convolution neural network,random forest,and logistic regression.The results show that the areas under the receiver operating characteristic curve(AUCs)of the optimal dataset for the abovementioned ML models are 0.963,0.961,and 0.930 which are higher than those of the original dataset(0.938,0.947,and 0.900)and statistical dataset(0.948,0.954,and 0.897).In conclusion,the RDC method can extract the more representative features from environmental factors and outperform the other conventional discretization methods.