Adaptive sampling and reconnaissance surveys for geostatistical mapping of the soil
Adaptive sampling and reconnaissance surveys for geostatistical mapping of the soil
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DOI：
10.1111/j.1365-2389.2005.00774.x
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发表时间：
2006-12-01
影响因子：
4.2
通讯作者：
Lark, R. M.
中科院分区：
文献类型：
--
作者：
Marchant, B. P.;Lark, R. M.
调查土壤变量所需的努力取决于估计值的可接受不确定性和变量的变异函数。变差函数在抽样之前是未知的，因此在设计有效的调查之前，必须从普查中推断出变差函数。普查的结果是受不确定性，这取决于变异函数和观测的数量和位置。在这里，我们开发了一个自适应方法优化普查。在这些侦察调查中的观察是在不同的阶段收集的。在每个阶段之后，在贝叶斯框架内计算主要调查所需抽样密度的概率密度函数。进一步的阶段内的观测值的数量和位置的选择，以有效地减少所需的抽样密度的估计的不确定性。在模拟研究中，在贝叶斯自适应侦察调查的观测值的数量和位置根据感兴趣的属性的变差函数而变化。对于短距离的变异函数，普查是密集的，有很大比例的聚类位置。对于长范围的变量，需要更少、更均匀分布的位置。贝叶斯自适应侦察调查导致更有效的调查比传统的方法，因为侦察调查是专门设计的变量的利益。一个手持现场系统的实施和测试中的土壤水分含量的调查领域。
The effort required to survey a soil variable depends upon the acceptable uncertainty of estimates and the variogram of the variable. The variogram is unknown prior to sampling, so it must be inferred from a reconnaissance survey before an efficient survey can be designed. The results of reconnaissance surveys are subject to uncertainty, which depends upon the variogram and the number and location of observations.Here, we develop an adaptive approach for optimizing reconnaissance surveys. The observations within these reconnaissance surveys are collected in distinct phases. After each phase, a probability density function of the required sampling density of the main survey is calculated within a Bayesian framework. The number and location of observations within further phases are selected to reduce efficiently the uncertainty of the estimate of the required sampling density.In simulation studies, the number and location of observations in Bayesian adaptive reconnaissance surveys vary according to the variogram of the property of interest. For variograms with a short range, the reconnaissance surveys are intensive with a large proportion of clustered locations. Fewer, more evenly spread locations are required for variables with a long range. Bayesian adaptive reconnaissance surveys lead to more efficient surveys than conventional approaches because the reconnaissance survey is specifically designed for the variable of interest. A hand-held field system is implemented and tested in a survey of soil moisture content over a field.