基于时空Kriging方法建立深度基准面模型     

袁建刚  章鹏 《测绘与空间地理信息》2017,(12):219-220,224

深度基准面是一个呈阶梯状、不连续的基准面,该特点给海洋测绘及相关活动带来严重的影响。目前建立深度基准面模型的方法有很多,一般采用几何插值方法,其函数模型大多以数据点的位置关系为基础。本文使用时空Kriging法建立深度基准面模型,时空Kriging法综合考虑了海面在时间和空间上的变化特征,通过构建不可分离型时空变异函数,对深度基准值进行插值拟合,并通过实例证实了拟合后的深度基准面模型的精度更高、连续性更好。  相似文献   

The storage potential of different surface coverings for various scale storms on Wu-Tu watershed,Taiwan     

Shin-Jen Cheng  Huey-Hong Hsieh  Cheng-Feng Lee  Yu-Ming Wang 《Natural Hazards》2008,44(1):129-146

An impervious surface cover is continuously spreading over the Wu-Tu upstream watershed due to the concentrated population and raised economical demands, while that area also frequently suffers from heavy storms or typhoons during the summer season. The increased flood volume due to this extended imperviousness causes a greater potential hazard than that of the past. In order to evaluate the urbanized impacts on the watershed, a set of methods were used to estimate the changes of the watershed storage. This research chose 51 observed events from three raingauges on the Wu-Tu upstream watershed, Taiwan, to study the volume characteristic of abstracted rainwater. In the study, the block Kriging method was used to estimate the area rainfall and the hourly excess was derived through the non-linear programing (NLP). A total of 40 samples were calibrated through the hydrological model and the Soil Conservation Service (SCS) model using the optimum seeking method in order to search out and establish the best parameters that illustrate the hydrological and geomorphic conditions at that time. Eleven cases were used to examine the established relationship of the parameters and the impervious coverings. A design storm approach was used to view the changes of the volume for various scale storms/typhoons because of the different degrees of urbanization. Then, a diagram was designed to show the relationships that exist among the runoff coefficient, return period, and impervious surface. The satisfactory results show that storage capability of rainwater for various scale storms on the Wu-Tu watershed would be respectively reduced about 42–156 cms in different decrements up to now.  相似文献   

附带星历参数的星载合成孔径雷达影像自动配准算法     

陈富龙  王超  张红  吴樊 《遥感学报》2008,12(4)

Fourier-Mellin不变性对称相位匹配滤波器,即symmetric phase-only matched flitering of fourier-mellin invariant(SPOMF-FMI)能解决影像配准的平移、旋转和放缩几何变换问题;然而,该方法在实际应用中具有局限性,包括图像几何尺度和图像非线性几何畸变处理能力.为了克服上述缺陷,提出了一种附带星载参数的星载合成孔径雷达(synthetic aperture radar,SAR)影像自动配准算法.该方法采用由粗到精匹配策略,由距离-多普勒影像粗匹配和改进SPOMF-FMI影像精匹配组成.使用Radarsat-1和ENVISAT ASAR影像做实验,结果表明本方法在处理重复轨道或相同升、降轨星载SAR影像(即确保相似影像纹理测度)配准问题时,能达到子像素级的配准精度.  相似文献   

空间预测的地统计学框架(英文)   总被引：2，自引：0，他引：2  

Jingxiong Zhang  Na Yao 《地球空间信息科学学报》2008,11(3):180-185

Geostatistics provides a coherent framework for spatial prediction and uncertainty assessment, whereby spatial dependence, as quantified by variograms, is utilized for best linear unbiased estimation of a regionalized variable at unsampied locations. Geostatistics for prediction of continuous regionalized variables is reviewed, with key methods underlying the derivation of major variants of uni-vafiate Kriging described in an easy-to-follow manner. This paper will contribute to demysti- fication and, hence, popularization of geostatistics in geoinformatics communities.  相似文献   

On a stronger-than-best property for best prediction   总被引：1，自引：1，他引：0  

P. J. G. Teunissen 《Journal of Geodesy》2008,82(3):167-175

The minimum mean squared error (MMSE) criterion is a popular criterion for devising best predictors. In case of linear predictors, it has the advantage that no further distributional assumptions need to be made, other then about the first- and second-order moments. In the spatial and Earth sciences, it is the best linear unbiased predictor (BLUP) that is used most often. Despite the fact that in this case only the first- and second-order moments need to be known, one often still makes statements about the complete distribution, in particular when statistical testing is involved. For such cases, one can do better than the BLUP, as shown in Teunissen (J Geod. doi: 10.1007/s00190-007-0140-6, 2006), and thus devise predictors that have a smaller MMSE than the BLUP. Hence, these predictors are to be preferred over the BLUP, if one really values the MMSE-criterion. In the present contribution, we will show, however, that the BLUP has another optimality property than the MMSE-property, provided that the distribution is Gaussian. It will be shown that in the Gaussian case, the prediction error of the BLUP has the highest possible probability of all linear unbiased predictors of being bounded in the weighted squared norm sense. This is a stronger property than the often advertised MMSE-property of the BLUP.  相似文献   

线性模型的泛最小二乘法     

胡宏昌  游雪肖  徐侃 《测绘科学》2008,33(2):101-103,74

本文首先针对线性模型提出了泛最小二乘法,在设计矩阵不加限制的情形下,得到了参数的泛最小二乘估计量。该方法既发扬了最小二乘法的优点,又克服了它的一些不足,它包含了常见的岭估计和最小二乘估计法;其次讨论了泛最小二乘法的理论依据;接着研究了泛最小二乘估计量的一些统计性质,并与最小二乘估计进行比较,在一定意义上前者优于后者;然后讨论了平衡参数的选取问题;最后,给出一个应用,说明了泛最小二乘法的有效性和可行性。  相似文献   

Comparison analysis of sampling methods to estimate regional precipitation based on the Kriging interpolation methods: A case of northwestern China   总被引：1，自引：0，他引：1  

JinKui Wu  ShiWei Liu  LePing M  Jia Qin  JiaXin Zhou  Hong Wei 《寒旱区科学》2016,8(6):485-494

The accuracy of spatial interpolation of precipitation data is determined by the actual spatial variability of the precipitation, the interpolation method, and the distribution of observatories whose selections are particularly important. In this paper, three spatial sampling programs, including spatial random sampling, spatial stratified sampling, and spatial sandwich sampling, are used to analyze the data from meteorological stations of northwestern China. We compared the accuracy of ordinary Kriging interpolation methods on the basis of the sampling results. The error values of the regional annual precipitation interpolation based on spatial sandwich sampling, including ME(0.1513), RMSE(95.91), ASE(101.84), MSE(-0.0036), and RMSSE(1.0397), were optimal under the premise of abundant prior knowledge. The result of spatial stratified sampling was poor, and spatial random sampling was even worse. Spatial sandwich sampling was the best sampling method, which minimized the error of regional precipitation estimation. It had a higher degree of accuracy compared with the other two methods and a wider scope of application.  相似文献   

The efficacy of Kriging spatial interpolation for filling temporal gaps in daily air temperature data: A case study in northeast China     

YanLin Zhang  XiaoLi Chang  Ji Liang  DongLiang Luo  RuiXia He 《寒旱区科学》2016,8(5):441-449

Quality-controlled and serially complete daily air temperature data are essential to evaluating and modelling the influences of climate change on the permafrost in cold regions. Due to malfunctions and location changes of observing stations, temporal gaps (i.e., missing data) are common in collected datasets. The objective of this study was to assess the efficacy of Kriging spatial interpolation for estimating missing data to fill the temporal gaps in daily air temperature data in northeast China. A cross-validation experiment was conducted. Daily air temperature series from 1960 to 2012 at each station were estimated by using the universal Kriging (UK) and Kriging with an external drift (KED), as appropriate, as if all the observations at a given station were completely missing. The temporal and spatial variation patterns of estimation uncertainties were also checked. Results showed that Kriging spatial interpolation was generally desirable for estimating missing data in daily air temperature, and in this study KED performed slightly better than UK. At most stations the correlation coefficients (R²) between the observed and estimated daily series were >0.98, and root mean square errors (RMSEs) of the estimated daily mean (T_mean), maximum (T_max), and minimum (T_min) of air temperature were <3℃. However, the estimation quality was strongly affected by seasonality and had spatial variation. In general, estimation uncertainties were small in summer and large in winter. On average, the RMSE in winter was approximately 1℃ higher than that in summer. In addition, estimation uncertainties in mountainous areas with complex terrain were significantly larger than those in plain areas.  相似文献   

地磁异常数据格网化最优方法     

聂琳娟  张兵兵  邱耀东 《测绘科学》2016,41(10):35-39,99

针对不同的格网化方法将影响地磁异常数据区域建模的精度,该文利用改进的谢别德法、克里格法、连续曲率样条法将空间分辨率为10′×10′的地磁异常数据内插得到2′×2′的地磁异常;并对这3种方法所获得的结果进行精度评定。结果表明,连续曲率样条法获得的结果最佳,其次是改进的谢别德法和克里格法。  相似文献   

基于地统计学和克里金法的水下趋势面分析   总被引：1，自引：0，他引：1  

陈科  李正品  杨林波  孙嘉骏 《测绘与空间地理信息》2016,(7):82-84

介绍了地统计学和克里金法对水深数据进行分析的方法和原理,结合工程实践,分析了水深值在沿垂直河道方向具有的空间自相关性,根据半变异函数模型,建立了水下趋势面模型,预测了未采样区域的水深值,并对结果进行了检核。实例分析结果表明:地统计学和克里金法在研究水深数据的空间格局和预测未知采样数据方面具有较强的优势,并能建立满足后续专业应用需求的水下趋势面模型。  相似文献