Quantification of spatial gradation of slope positions   总被引：6，自引：0，他引：6  

Cheng-Zhi Qin  A-Xing Zhu  Xun Shi  Bao-Lin Li  Tao Pei  Cheng-Hu Zhou 《Geomorphology》2009,110(3-4):152-161

Transition between slope positions (e.g., ridge, shoulder slope, back slope, foot slope, and valley) is often gradual. Quantification of spatial transitions or spatial gradations between slope positions can increase the accuracy of terrain parameterization for geographical or ecological modeling, especially for digital soil mapping at a fine scale. Current models for characterizing the spatial gradation of slope positions based on a gridded DEM either focus solely on the parameter space or depend on too many rules defined by topographic attributes, which makes such approaches impractical. The typical locations of a slope position contain the characteristics of the slope position in both parameter space and spatial context. Thus, the spatial gradation of slope positions can be quantified by comparing terrain characteristics (spatial and parametrical) of given locations to those at typical locations. Based on this idea, this paper proposes an approach to quantifying the spatial gradation of slope positions by using typical locations as prototypes. This approach includes two parts: the first is to extract the typical locations of each slope position and treat them as the prototypes of this position; and the second is to compute the similarity between a given location and the prototypes based on both local topographic attributes and spatial context. The new approach characterizes slope position gradation in both the attribute domain (i.e., parameter space) and the spatial domain (i.e., geographic space) in an easy and practicable way. Applications show that the new approach can quantitatively describe spatial gradations among a set of slope positions. Comparison of spatial gradation of A-horizon sand percentages with the quantified spatial gradation of slope positions indicates that the latter reflects slope processes, confirming the effectiveness of the approach. The comparison of a soil subgroup map of the study area with the maximum similarity map derived from the approach also suggests that the quantified spatial gradation of slope position can be used to aid geographical modeling such as digital soil mapping.  相似文献   

颗粒分析试验研究     

李瑜霞 《岩土工程技术》2010,24(4):198-201

颗粒分析试验是测定干土中各种粒组所占该土总质量的百分数的方法,借以明了颗粒大小分布情况,供土的分类及粗略判断土的工程性质及建筑材料选料之用,其中的密度计法用于测定小于0.075 mm以下的颗粒大小及分布情况,测量的准确度直接关系到土中黏粒和胶粒的多少,在试验的角度分析了密度计法试验结果误差的原因,指出现行规范中温度校正的不合理性,提出了空白试验方法,供工程技术人员和土工试验人员参考并验证.  相似文献   

要素市场化中的 “公共人“效率三题     

牛福增 《广东海洋大学学报》2004,24(2):17-21

政府作为"公共人"在要素市场培育过程中作用发挥的程度取决于政府效率本身.从政府效率的重要性与紧迫性、政府效率的特殊性、政府效率的层次性三个方面进行必要的界说与分析,并揭示其内在的规定性.  相似文献   

彩色图像的输入指标对层次再现的影响   总被引：1，自引：0，他引：1  

马桃林 《武汉大学学报(信息科学版)》2005,30(9):829-832,845

层次和细微层次是评价图像复制质量的重要指标。对两种常用平台式扫描仪的输入指标进行检测,通过分析和对比实验,研究了各指标的作用规律,并分析其对图像层次和细微层次的影响,对不同类型的彩色原稿的扫描指数的设置都具有一定的指导意义。  相似文献   

地球化学负异常及其找矿意义   总被引：7，自引：0，他引：7  

朴寿成  刘树田 《地质与勘探》1996,32(2):46-50

地球化学负异常的存在具有普遍性。完整的地球化学异常场应包括正异常场和负异常场。负异常按其规模和找矿意义可分为区域、矿床和矿体３个不同层次。区域负异常，可以指明区域找矿方向，圈定找矿靶区；矿床负异常指出矿床可能存在的地段；矿体负异常具体圈定矿体存在的空间位置。负异常与正异常的综合研究，有助于深化对矿床成因的认识，扩大找矿信息，提高找矿效果。  相似文献   

堆石体粒径特征对其渗透性的影响   总被引：19，自引：2，他引：19  

邱贤德  阎宗岭  刘立  王辉 《岩土力学》2004,25(6):950-954

堆石体属于典型的多孔材料,其渗透特性与颗粒的形状、大小及分布特征关系密切。研究表明,在渗流速度较大时应对达西定律加以修正。结合堆石体颗粒的概率统计分布模型,建立了堆石体颗粒含量与渗透系数之间的经验关系式,把渗透率和堆石体的粒径特征结合起来。在工程设计中可以通过合理调整堆石体的粒径级配,达到控制其渗透能力的目的。  相似文献   

城市土地级别划分的方法研究——以北京城市土地定级为例   总被引：3，自引：0，他引：3  

姜安源  马修军  魏黎  杜海鹏 《地域研究与开发》2002,21(2):9-12

城市土地定级是制订基准地价的基础，也是有效进行土地资源合理配置和土地管理的重要手段，文章主要探讨空间插值方法在北京城市土地定级中的应用，认为空间插值算法是一种通过已知点的数据推求同一区域其它未知点数据的计算方法，在土地市场发达，土地交易案例较多的城镇，可以适用于运用市场交易地价划分土地级别。  相似文献   

基于GIS的城市规划用地定级研究——以辽宁沿海产业基地为例     

张恒  沈体雁  刘少峰 《国土资源信息化》2008,(6):24-24,25-27,35

本文以辽宁(营口)沿海产业基地一期用地规划为例,根据自然条件、环境条件、社会条件等多个因素建立一套用地定级指标体系。采用GIS强大的分析功能综合分析总体规划区范围内三种用地(居住用地,商业用地,商业办公用地)的土地等级,结合ESRI的ArcObject组件和VS.net平台建立用地定级的计算平台,以便快速进行定级结果的计算。为城市规划、管理、经营提供定量的分析指标。  相似文献   

A perturbation solution for dyke propagation in an elastic medium with graded density   总被引：1，自引：0，他引：1  

Zuan Chen  Z.-H. Jin  S. E. Johnson 《Geophysical Journal International》2007,169(1):348-356

  相似文献   

Method study of classification and gradation of earthquake disasters     

毛国敏顾建华  吴新燕 《地震学报(英文版)》2007,20(4):454-466

Based on data of earthquake disaster events during 1954~2005 in the Chinese mainland, the classification and gradation of earthquake disasters have been studied by multivariate statistical analysis. Three fundamental structures of earthquake disasters have been found and an FAPE (factor analysis-principal component-equamax rotation) classification model and an HCWS (hierarchical cluster-ward method-seuclid) gradation model have been constructed. Earthquake disasters are divided into eight classes and five grades respectively in the models, which give a reasonable explanation to the phenomenon of earthquake disasters.  相似文献