Monotone Regression and Correction for Order Relation Deviations in Indicator Kriging

The indicator kriging (IK) is one of the most efficient nonparametric methods in geo-statistics. The order relation problem in the conditional cumulative distribution values obtained by IK is the most severe drawback of it. The correction of order relation deviations is an essential and important part of IK approach. A monotone regression was proposed as a new correction method which could minimize the deviation from original quintiles value, although, ensuring all order relations.     

Spatial variability and pattern analysis of soil properties in Dehui city, Jilin province

1IntroductionSoil nutrient, as the synthetic results under the influence of various anthropogenic activities and the factors such as climate and topography, etc., possesses certain spatial distribution characteristics, and certain structural and stochastic characteristics. The study of the differences existing in different parts of the region lays the foundation for adjusting all management measures and all material input capacities and for gaining the maximal economic benefit. Presently, the …     

Influence of groundwater level change on vegetation coverage and their spatial variation in arid regions

Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application of geo-statistics. Results showed that the variance curve of the groundwater depth and vegetation coverage displays an exponential model. Analysis of sampling data in 2003 indicates that the groundwater depth and vegetation coverage change similarly in space in this area. The Sangong River Basin is composed of upper oasis, middle ecotone and lower sand dune. In oasis and ecotone, influenced by irrigation of the adjoining oasis, groundwater level has been raised and soil water content also increased compared with sand dune nearby, vegetation developed well. But in the lower reaches of the Sangong River Basin, because of descending of groundwater level, soil water content decreased and vegetation degenerated. From oasis to abandoned land and desert grassland, vegetation coverage and groundwater level changed greatly with significant difference respectively in spatial variation. Distinct but similar spatial variability exists among the groundwater depth and vegetation coverage in the study area, namely, the vegetation coverage decreasing (increasing) as the groundwater depth increases (decreases). This illustrates the great dependence of vegetation coverage on groundwater depth in arid regions and further implies that among the great number of factors affecting vegetation coverage in arid regions, groundwater depth turns out to be the most determinant one.     

广西土壤有机质空间变异特征及其影响因素研究

基于广西第二次土壤普查的270个土壤剖面资料,结合1∶50万数字化土壤类型图、土地利用类型图和气象监测数据等资料,利用地统计学和逐步回归分析等方法对广西表层土壤有机质空间变异特征及其影响因素进行了探究。结果表明：广西表层土壤有机质平均含量为3.11±2.19%,变异系数为70.72%,空间分布呈北高南低的趋势。广西表层土壤有机质空间分布受到自然和人为因素的共同影响,土壤类型、成土母质、海拔、土地利用、气候和坡度6个环境因子对全区土壤有机质含量变异的综合解释能力为47.9%。其中,土壤类型是最重要的影响因素,能独立解释其变异的36.0%,海拔和成土母质分别能独立解释28.5%和15.8%。气温对广西土壤有机质空间分布的影响比降水量更加显著,从而造成了广西土壤有机质整体呈南低北高的趋势。同时,土壤有机质对气温的敏感性在一定程度上受到降雨量的制约。此外,研究区农业耕作管理等因素对土壤有机质的影响也不容忽视。     

求解半变异函数的常用方法与新方法研究

半变异函数的获取既有人为主观求取法,又有运用数学工具客观求取法,但是后者是今后的主要趋势。笔者在前人工作的基础上,归纳出多项式回归法、线性规划法和目标规划法三种求解半变异函数的成熟方法,以及非线性回归理论直接求解法、进化计算和积分面积三种新兴方法,并总结出各种方法的优缺点。最后概括出计算权重的两种方法。     

黑龙江省穆棱市土地利用/覆被变化及热点分析

土地利用/覆被变化及其过程特征是全球变化领域研究的重点和热点。运用地统计学和3S技术,对黑龙江省穆棱市1991—2001年和2001—2013年土地利用/覆被变化及其空间演变特征进行研究。结果表明:1991—2001年间,耕地是主要转入地类,增加232.25 km~2,林地作为最大转出地类,减少290.35 km~2,林地与耕地的转化在土地利用变化中占最大比例,其他用地均发生变化,但面积小且散乱,整体上该时期土地利用呈现出开发混乱、效率低下的特点;2001—2013年间,受还林还草的影响,耕地减少179.01 km~2,林地增加171.45 km~2,其中坡耕地的退出占较大比例,且分布面积广,该时段内土地利用结构得到优化;土地利用变化的热点区由2001年前的"两大一小"模式,演变为以市区和中心乡镇围成的重点区域;1991—2013年间研究区自然因子变化较小,土地利用/覆被变化主要受退耕还林等国家政策的主导。     

中国大陆现时地壳水平运动特征及其驱动机制

利用1999—2007年中国大陆及邻区在ITRF2007参考框架下的1 068个GPS观测成果,以地统计分析为基础,应用运动学研究方法,分析了中国大陆及邻区地壳表层速度场的分布特征,以及印度、欧亚、菲律宾、太平洋4大板块在相互作用过程中,对中国大陆及其邻区地壳表层运动与变形分布的影响范围和程度以及驱动机制进行了分析。     

动态构建福建紫金山铜金矿矿体模型

为了将不同边界品位情况下矿体的形态及由边界品位变化引起的矿体形态变化程度在计算机中动态、实时地展现,同时也为了解矿体在不同工业指标条件下的空间形态,进行了矿体动态建模方法研究。采用了一种新的、基于矿体属性模型向其几何结构模型转化的方法--克里格块体法。通过该方法,基于指示克里格估值技术,使用块体模型＋实体模型的三维数据模型结构,动态地构建出了福建上杭紫金山铜金矿矿体在不同边界品位条件下、信息充分、完备且具高可信度的矿体模型,达到了使建模结果能够真正服务于矿山勘探和生产实践的效果。该方法具有一定的可扩展和易推广的性质,能够完成大多数类似矿山及类似地质体的动态建模过程。     

基于地质统计学反演的碳酸盐岩孔缝洞预测研究

提出一种基于地质统计反演的碳酸盐岩孔缝洞预测方法:首先,根据碳酸盐岩矿物成分,利用电阻率曲线和三孔隙度曲线计算单井裂缝孔隙度和次生孔隙度;然后,利用地质统计反演分别预测裂缝以及溶孔溶洞的平面分布特征;最后,通过综合分析得到碳酸岩储层的孔缝洞发育区带。将该方法应用于研究区碳酸盐岩储层的孔缝洞预测中,得到的孔缝洞分布特征与已知的白云岩分布特征较为吻合,验证了该方法的有效性。     

Modelling and predicting the spatial dispersion of skin cancer considering environmental and socio-economic factors using a digital earth approach

ABSTRACT

Almost all causative factors of diseases depend on location. The Digital Earth approach is suitable for studying diseases globally. Geospatial information systems integrated with statistical models can be used to model the relationship between a disease and its causative factors. Through modelling, the most important causative factors can be extracted and the epidemiology of the disease can be observed. In this paper, skin cancer (the most common type of cancer) has been modelled based on its causative factors, including climate factors, people's occupations, nutrition habits, socio-economic factors, and usage of chemical fertiliser. To fit the model, a data framework was first designed, and then data were gathered and processed. Finally, the disease was modelled using Generalised Linear Models (GLM), a statistical model based on the location of the factors. The results of this study identify the most important causative factors together with their relative priority. Furthermore, a model was used to predict the change in skin cancer occurrences caused by a change in one of its causative factors. This work illustrates the ability of the model to predict disease occurrence. Thus, by using this Digital Earth approach, skincancer can be studied in all the key countries around the world.