Mapping local regression for spatial object-pairs     

Jie Lin  Robert G. Cromley  Dean M. Hanink 《制图学和地理信息科学》2016,43(4):328-337

Local regression methods such as geographically weighted regression (GWR) can provide specific information about individual locations (or places) in spatial analysis that is useful for mapping nonstationary covariate relationships. However, the distance-based weighting schemes used in GWR are only adaptable for spatial objects that are point or area features. In particular, spatial object-pairs pose a challenge for local analysis because they have a linear dimensionality rather than a point dimensionality. This paper proposes using an alternative local regression model – quantile regression (QR) – for investigating the stationarity of regression parameters with respect to these linear features as well as facilitating the visualization of the results. An empirical example of a gravity model analysis of trade patterns within Europe is used to illustrate the utility of the proposed method.  相似文献   

Spatial variability of soil erodibility and its correlation with soil properties in semi-arid mountainous watershed,Saudi Arabia   总被引：2，自引：0，他引：2  

Javed Mallick  Hussein Al-Wadi  Atiqur Rahman  Mohd Ahmed  Roohul Abad Khan 《国际地球制图》2016,31(6):661-681

Soil erodibility values are best estimated from long-term direct measurements on runoff-plots; however, in lack of field tests, these values can be estimated using relationships based on physico-chemical soil properties. The study objective was to assess the erodibility and its correlation with soil properties. The average erodibility value was estimated 0.043 t ha h ha^?1 MJ^?1 mm^?1. The areas with heavy textured soil and low organic matter content had the lowest values of erodibility. The erodibility decreases as the sand content increases, whereas silt showed a positive correlation. The erodibility factors and its relation to soil properties were evaluated using multiple regression analysis. Results revealed that sand and organic matter content of soil combinedly explained 78% of variation. Altitudinal increases also seem to affect the soil texture. This study has demonstrated that soil properties and erodibility values can be used as assistance for soil conservation practices and modelling of landscape processes.  相似文献   

新阈值及阈值函数的评价和变形预测实验     

张俊鑫 《测绘与空间地理信息》2016,(7):195-197

变形监测数据是判断对象是否会发生异常变化的重要依据,但实测数据会被带入噪声,将隐藏其实际变化规律。本文利用含有高斯白噪声的信号来评价两种新的阈值及阈值函数的去噪效果,并评价两种新的阈值及阈值函数在提高预测精度方面的效果。实验表明,较传统的硬/软阈值函数,两种新阈值及阈值函数的去噪效果更优,而且该组合方法提高了预测的可靠性和精度。  相似文献   

滑坡监测数据处理回归模型分析及探讨     

张纯志 《测绘与空间地理信息》2016,(8)

主要介绍了滑坡监测的技术和方法,并通过万源市太平镇某滑坡监测实践,阐述了在地形复杂、观测条件恶劣的山区进行滑坡监测时,基准监测点选择、监测网布设、数据处理的方法。最重要的是用线性回归方程分析监测数据,为科学治理提供可靠的依据。  相似文献   

基于核半监督判别分析的高光谱影像特征提取     

张鹏强  谭熊  余旭初  魏祥坡  薛志祥 《测绘科学技术学报》2016,(3)

针对高光谱影像特征提取中地物类别训练样本获取代价较高的情况,在线性判别分析的基础上,结合核方法和半监督学习理论,提出了一种基于核半监督判别分析(KSDA)的高光谱影像特征提取方法。该方法同时利用少量已知类别和大量未知类别样本数据进行模型的学习和训练。通过OMIS高光谱影像数据实验表明:在少量已知类别训练样本的条件下,经KSDA特征提取的样本数据在特征空间中能更好地聚集成团,且类别之间的距离较大,增加了类别之间的可分性,得到了较高的分类精度;同时,提取的特征影像能够较好地区分各种地物类别。  相似文献   

中哈能源消费结构与能源安全关联性对比分析     

刘明辉  袁培  卢飞 《世界地理研究》2016,(3):49-58

能源产业作为丝绸之路经济带建设的首推工程,影响丝绸之路经济带建设的整体进程。文章以能源消费结构为切入点,构建能源供应安全和使用安全的指标体系,运用回归方法对比分析了1992年~2013年中哈两国能源消费结构与能源安全的关联性。研究结果表明:两国传统的能源消费结构对能源安全的贡献呈现逐渐下降的趋势;两国能源安全均呈现"波动上升-波动下降"演进特征;两国能源安全形势都较为严峻,能源使用安全产生的环境负面效应凸显并逐渐放大。鉴于此,文章以两国能源合作为基础,从区域一体化层面审视并探究两国能源安全合作的深化路径。  相似文献   

Space–time multiple regression model for grid-based population estimation in urban areas     

Ko Ko Lwin  Komei Sugiura  Koji Zettsu 《International journal of geographical information science》2016,30(8):1579-1593

We can collect, store, and analyze a huge amount of information about human mobility and social interaction activities due to the emergence of information and communication technologies and location-enabled mobile devices under cyber physical system frameworks. The high spatial resolution of population data on a multi-temporal scale is required by transport planners, human geographers, social scientists, and emergency management teams. In this study, we build a space-time multiple regression model to estimate grid-based (500 m × 500 m) spatial resolution at multi-temporal scale (30-min intervals) population data based on the space-time relationship among geospatially enabled person trip (PT) survey data and incorporate both mobile call (MC) and geotagged Twitter (GT) data. Since using geospatially enabled PT survey data as dependent variables enables us to acquire actual population amounts, which strongly depend on MCs and social interaction activities. Although many grids have a strong correlation between PT and MC/GT, some show fewer correlation results, especially where the grids have factories, schools, and workshops in which fewer MCs are found but a large population is presented. Although GT data are sparser than MCs, people from amusement and tourist areas can be detected by GT data. The space-time multiple regression model can also estimate the different amounts of populations based on human travel behavior that changes over space and time. According to accuracy assessments, the night-time estimated results, especially between 00:00 and 06:30, strongly correlate with national census data except in places where the grids have railway and subway stations.  相似文献   

Modeling the Invasion of Holly (Ilex aquifolium): Spatial Relationships and Spread Trajectories     

Santiago López  David L. Stokes 《The Professional geographer》2016,68(3):399-413

In this study, we investigated the environmental factors associated with the establishment of invasive English holly (Ilex aquifolium) and the spatiotemporal trajectories of its potential spread. We collected georeferenced presence and absence and demographic data of holly between 2011 and 2014 in Saint Edward State Park, Washington. We analyzed them through a spatially explicit framework that combines multiple logistic regression, cellular automata, and bivariate quadratic modeling. Results showed that the presence of holly is influenced by the proximity to evergreen coniferous vegetation and forest edge, distance to streams, forest structure, and slope direction. Our study confirmed that local environmental conditions, species characteristics, and vegetative and dispersal mechanisms play a significant role in determining the rate and success of holly establishment across the different phases of invasion. Invasive species management plans should consider both species characteristics and their habitat and the interactions among them when planning long-term strategies for control and eradication.  相似文献   

Comparison of spatial and aspatial logistic regression models for landmine risk mapping     

《Applied geography (Sevenoaks, England)》2016

Landmines continue to affect the lives of millions of people living in war-torn countries. One major challenge in humanitarian mine action (HMA) is finding new and integrated approaches to land release, which remains a slow and costly process. The use of geographic information systems (GIS) in HMA can improve the land release process by efficient mapping and prioritizing of landmine risk areas. This study explores the usage of aspatial and spatial regression techniques to construct a predictive geo-statistical model for landmine risk mapping in a small 160 km² municipality in Bosnia and Herzegovina (BiH) and a large 4500 km² region in Colombia. The first application of logistic geographically weighted regression to landmine risk mapping is presented. The results show that in the BiH study area, the effect of local parameters that influence the distribution of landmine risk varies significantly across the study area. Conversely, in the Colombia case study the effect of explanatory variables remains more homogeneous over the study area. We produced two landmine risk maps for each study area, based on aspatial and spatial regression models. Risk maps are classified into five classes, i.e. very low, low, medium, high, and very high risk. The landmine risk maps created through the usage of these innovative methodologies improve the assessment of risk and prioritization of the land release process in mine-contaminated areas, compared to existing approaches.  相似文献   

基于DMSP/OLS与NDVI的江苏省碳排放空间分布模拟     

郭忻怡  闫庆武  谭晓悦  刘思佳 《世界地理研究》2016,(4):102-110

结合江苏省经济结构和自然环境情况,选择合适的碳排放模型进行核算,得到江苏省各区县的碳排放量,综合DMSP/OLS夜间灯光影像和NDVI数据,再结合人口、GDP和工业生产总值数据,构建碳排放的空间滞后回归模型并开展江苏省碳排放的空间分布模拟,得到大小为1km×1km的碳排放空间格网,并对模拟结果纠正,用以研究江苏省各区县的碳排放量分布情况。结果表明,江苏省碳排放清晰地呈现出"苏南苏北苏中"的格局,苏南地区分布着以苏州、无锡为中心和以南京市区为中心的碳排放高值集聚的"热点"区域;在各区县内部,碳排放的空间分布与人口、GDP产值等密切相关,明显集中于人口、工业聚集的市区和县城区域。  相似文献