地图数字化位置误差的协方差函数   总被引：3，自引：1，他引：3  

蓝悦明  陶本藻 《武汉大学学报(信息科学版)》2004,29(1):63-66

针对数字化地图的精度 ,利用平稳随机过程的理论来估计位置数据的不确定性 ,提出了一套计算方法 ,主要内容包括运用平稳随机过程的各态历经性 ,对任意点坐标的X、Y按距离拟合求定其协方差 ,其特点是应用了统计估计原理 ,使得到的结果更为合理和简便。  相似文献   

集成高度和彩色纹理特征的影像目标模糊聚类识别方法     

潘励  郑宏  张祖勋  张剑清 《武汉大学学报(信息科学版)》2004,29(4):311-314

提出一种基于高度和彩色纹理信息的目标识别方法 ,其目的是提取具有相对高度的地物。由于传统二维纹理分析的方法往往不能有效地提取这类目标 ,本文把高度、色彩和纹理信息有机地结合起来 ,提高了识别率。依据影像提取结果 ,探讨了树林对森林覆盖地区自动空中三角测量选点的负面影响 ,同时建议采用数据分组的方案来改善森林覆盖地区自动空中三角测量的精度 ,并用对比实验证明了其有效性。  相似文献   

时间动态地图模型   总被引：2，自引：1，他引：2  

李霖  苗蕾 《武汉大学学报(信息科学版)》2004,29(6):484-487

就时间动态地图模型进行了研究，认为动态地图由于表达空间维数的增加，使得地图作为客观现实世界的概念模型更加完善，并且作为物质模型，动态地图的可视化应与空间认知的计算机表达紧密融合。在制作时间动态地图时，不同的视觉变量具有不同的动态表现能力，根据时态现象的特征进行选取。  相似文献   

近20年华北地电阻率异常空间演化及强震短期前兆判别标志研究     

郑文俊  田山  邵永新 《中国地震》2005,21(2):260-268

开展了华北地电阻率异常参数提取的研究，以1980—2001年的异常参数为输入进行了全时空扫描，并对其动态图像演化做全面分析，由此提取出华北地区5级以上地震的地电阻率短期前兆的判别标志。为了进行初步检验，本文依上述判别标志对华北近年地电阻率动态图像做了对比分析。  相似文献   

The coupling instability of Rossby and topographic Rossby waves in the equatorial area     

CHAO Jiping    LIU Lin  & YU Weidong . Laboratory of Marine Science  Numerical Modeling  State Oceanic Administration  Qingdao  China  . National Research Center for Marine Environmental Forecasts  State Oceanic Administration  Beijing  China  . Ocean University of China  Qingdao  China 《中国科学D辑(英文版)》2005,48(10)

Before the 1980s, El Ni?o was believed as the sea surface warming along the coast of Peru in South America. As the positive anomaly strengths, the warm water expands westward along the equator to form large area of anomalous high sea surface temperature. Rasmusson and Carpenter (1982) summarized the de-velopment process of the sea surface warm water and the corresponding wind field[1] during ENSO cylce. However, this canonical El Ni?o was questioned by 1982-1983 warm episode and later dat…  相似文献   

Adaptation of seismic skeletonization for other geoscience applications     

K. Vasudevan  D. Eaton  F. A. Cook 《Geophysical Journal International》2005,162(3):975-993

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Recovering acoustic reflectivity using Dirichlet-to-Neumann maps and left- and right-operating adjoint propagators   总被引：1，自引：0，他引：1  

M. W. P. Dillen  J. T. Fokkema  C. P. A. Wapenaar 《Geophysical Journal International》2005,163(1):106-125

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Reply to Discussion by Kayabali on “Attenuation relationship based on Turkish strong motion data and iso-acceleration map of Turkey” by Ulusay et al., Eng. Geol., 37 (2004)     

R. Ulusay  E. Tuncay  H. Sonmez  C. Gokceoglu 《Engineering Geology》2005,79(3-4):296-299

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中国东部大陆岩石地球化学图揭示的信息     

迟清华 《地质通报》2005,(Z1)

根据中国东部各省(区、市)区域地质志、1∶50万地质图和中国东部地壳与岩石元素丰度研究成果首次编制的中国东部60种元素的岩石地球化学图,基本反映了与特定岩性有关的区域岩石地球化学元素含量分布特征和与大地构造单元有关的区域地球化学元素含量分布特征,直观表达了中国东部空间地理上元素背景含量的宏观分布与变化,以及不同大地构造单元元素背景含量的变化趋势。这一成果为勘查地球化学、环境地球化学,特别是区域化探扫面水系沉积物资料的定量解释提供了基本依据,为基础地质、大地构造、区域成矿研究提供了重要资料,也为地球化学块体理论及其形成机制的研究提供了强有力的支持。  相似文献   

Development of a soil moisture‐based distributed hydrologic model for determining hydrologically based critical source areas          下载免费PDF全文

Sisi Li  Margaret Gitau  David Bosch  Bernard A. Engel  Liang Zhang  Yun Du 《水文研究》2017,31(20):3543-3557

A simple grid cell‐based distributed hydrologic model was developed to provide spatial information on hydrologic components for determining hydrologically based critical source areas. The model represents the critical process (soil moisture variation) to run‐off generation accounting for both local and global water balance. In this way, it simulates both infiltration excess run‐off and saturation excess run‐off. The model was tested by multisite and multivariable evaluation on the 50‐km² Little River Experimental Watershed I in Georgia, U.S. and 2 smaller nested subwatersheds. Water balance, hydrograph, and soil moisture were simulated and compared to observed data. For streamflow calibration, the daily Nash‐Sutcliffe coefficient was 0.78 at the watershed outlet and 0.56 and 0.75 at the 2 nested subwatersheds. For the validation period, the Nash‐Sutcliffe coefficients were 0.79 at the watershed outlet and 0.85 and 0.83 at the 2 subwatersheds. The per cent bias was less than 15% for all sites. For soil moisture, the model also predicted the rising and declining trends at 4 of the 5 measurement sites. The spatial distribution of surface run‐off simulated by the model was mainly controlled by local characteristics (precipitation, soil properties, and land cover) on dry days and by global watershed characteristics (relative position within the watershed and hydrologic connectivity) on wet days when saturation excess run‐off was simulated. The spatial details of run‐off generation and travel time along flow paths provided by the model are helpful for watershed managers to further identify critical source areas of non‐point source pollution and develop best management practices.  相似文献