基于OpenGIS规范的地理信息系统组件的内核及功能设计     

谈晓军  边馥苓  何忠焕 《武汉大学学报(信息科学版)》2004,29(1):38-42

提出了符合OpenGIS规范的二维地理信息系统组件软件MapManager的设计思想 ,介绍了MapManager的设计过程 ,并对其不足和进一步研究方向进行了讨论。  相似文献   

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   

用L-曲线法确定岭估计中的岭参数   总被引：15，自引：0，他引：15  

王振杰  欧吉坤 《武汉大学学报(信息科学版)》2004,29(3):235-238

运用L 曲线法来确定岭估计中的岭参数 ,推导了用L 曲线法确定岭参数的基本公式 ,在此基础上实现了其算法 ,并用两个算例 ,比较了新方法和以往方法。结果表明 ,L 曲线法不仅容易收敛 ,而且其计算结果的精度较高  相似文献   

Self-affinity dimensions of topography and its implications in morphotectonics: an example from Taiwan   总被引：1，自引：0，他引：1  

Quo-Cheng Sung  Yen-Chieh Chen   《Geomorphology》2004,62(3-4):181-198

This paper discusses the self-affinity dimensions of landscape surfaces at a short-range scale and the link to morphotectonic features of the young orogenic belts of Taiwan. The variogram method is adopted to estimate such parameters as the fractal dimension (D), the ordinate-intercept (γ) and the range (R) from data subsets of the digital elevation model (DEM) in a moving-window operation. The fractal morphology expressed by D and γ is found to be useful in defining geomorphic provinces that are related to tectonic features. The mountainous terrain is characterized by high gamma values and low fractal dimensions in contrast to the coastal plains where low gamma values and high fractal dimensions are found. A zone, defined by the fractal parameters (2.4<D<2.6 and 0<γ<2.4), is found to coincide with the most tectonically active zone of Taiwan. Active faults often occur at the boundary between landscapes with contrasting fractal patterns. In the flat lowlands along the western coast, the fractal morphology displays a west-facing amphitheatric pattern, which may be related to the indentation of the pre-Miocene Peikang Basement High. The fractal morphology may reflect some subtle changes in surface textures of a landscape sculpted by surface processes, which in turn are influenced by tectonic activities. The surface roughening and diffusive smoothing may concur to shape the landscape surface at the short ranges we discuss in this study.  相似文献   

Influence of groundwater level change on vegetation coverage and their spatial variation in arid regions   总被引：3，自引：0，他引：3  

SULTAN Danyar  SONG Yudong  MARINA Jumakeld 《地理学报》2004,14(3):323-329

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.  相似文献   

Constraints on density and shear velocity contrasts at the inner core boundary   总被引：3，自引：0，他引：3  

Aimin Cao  Barbara Romanowicz 《Geophysical Journal International》2004,157(3):1146-1151

  相似文献   

Spectral element modelling of three-dimensional wave propagation in a self-gravitating Earth with an arbitrarily stratified outer core     

Emmanuel Chaljub  Bernard Valette 《Geophysical Journal International》2004,158(1):131-141

  相似文献   

Using commercial finite element packages for the study of earth deformations, sea levels and the state of stress   总被引：5，自引：0，他引：5  

Patrick Wu 《Geophysical Journal International》2004,158(2):401-408

  相似文献   

Wave propagation across fluid–solid interfaces: a grid method approach     

Jianfeng Zhang 《Geophysical Journal International》2004,159(1):240-252

  相似文献   

Numerical modelling method for wave propagation in a linear viscoelastic medium with singular memory   总被引：1，自引：0，他引：1  

Jian-Fei Lu  Andrzej Hanyga 《Geophysical Journal International》2004,159(2):688-702

  相似文献