Second-Phase Sampling Designs for Non-Stationary Spatial Variables.
Second-Phase Sampling Designs for Non-Stationary Spatial Variables.
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DOI：
10.1016/j.geoderma.2009.08.007
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发表时间：
2009-10-15
期刊：
影响因子：
6.1
通讯作者：
Goovaerts P
中科院分区：
文献类型：
--
作者：
Delmelle EM;Goovaerts P
在空间采样中，一旦收集了主要变量的初始样本，就可以进行额外的测量，这种方法称为第二阶段采样。额外的样本通常在远离观测位置或克里金方差最大的地方收集。然而，克里金方差（也称为预测误差方差）与数据值无关，并且是在平稳空间过程的假设下计算的，这在实践中经常被违反。在本文中，我们加权克里金方差与另一个标准，提供更大的采样重要性的位置表现出显着的空间粗糙度计算的空间移动平均窗口。由于加权目标函数是非线性的，因此使用模拟退火过程分配额外的样本。一个案例研究使用详尽的遥感图像说明了这一过程。组合的第一阶段系统和嵌套的抽样设计（或模式）的不同密度的产生，而额外的观察的位置是指导的方式，优化建议的目标函数。提取新点处的真实像素值，更新半变异函数模型，并重建图像。第二阶段的采样模式优化建议的标准导致预测更接近真实的图像比使用克里金方差作为主要标准时。当第一相样品的密度较低时，这种改善更强，但是随着初始密度的增加而降低。
In spatial sampling, once initial samples of the primary variable have been collected, it is possible to take additional measurements, an approach known as second-phase sampling. Additional samples are usually collected away from observation locations, or where the kriging variance is maximum. However, the kriging variance (also known as prediction error variance) is independent of data values and computed under the assumption of stationary spatial process, which is often violated in practice. In this paper, we weight the kriging variance with another criterion, giving greater sampling importance to locations exhibiting significant spatial roughness that is computed by a spatial moving average window. Additional samples are allocated using a simulated annealing procedure since the weighted objective function is non-linear. A case study using an exhaustive remote sensing image illustrates the procedure. Combinations of first-phase systematic and nested sampling designs (or patterns) of varying densities are generated, while the location of additional observations is guided in a way which optimizes the proposed objective function. The true pixel value at the new points is extracted, the semivariogram model updated, and the image reconstructed. Second-phase sampling patterns optimizing the proposed criterion lead to predictions closer to the true image than when using the kriging variance as the main criterion. This improvement is stronger when there is a low density of first-phase samples, and decreases however as the initial density increases.
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DOI：
10.1080/13658810110099125
发表时间：
2002-03-01
影响因子：
5.7
作者：
Goovaerts, P
通讯作者：
Goovaerts, P
DOI：
10.1016/0960-1686(90)90508-k
发表时间：
1990-01-01
期刊：
ATMOSPHERIC ENVIRONMENT PART A-GENERAL TOPICS
影响因子：
--
作者：
HAAS, TC
通讯作者：
HAAS, TC
DOI：
10.1023/a:1007511923053
发表时间：
1999-07-01
期刊：
MATHEMATICAL GEOLOGY
影响因子：
--
作者：
Bueso, MC;Angulo, JM;García-Aróstegui, JL
通讯作者：
García-Aróstegui, JL
影响因子：
2.7
作者：
BELLHOUSE, DR
通讯作者：
BELLHOUSE, DR
影响因子：
5.4
作者：
CHRISTAKOS, G;KILLAM, BR
通讯作者：
KILLAM, BR