How should a spatial-coverage sample design for a geostatistical soil survey be supplemented to support estimation of spatial covariance parameters?

We use an expression for the error variance of geostatistical predictions, which includes the effect of uncertainty in the spatial covariance parameters, to examine the performance of sample designs in which a proportion of the total number of observations are distributed according to a spatial cove...

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Main Authors: Lark, Murray, Marchant, B.P.
Format: Article
Published: Elsevier 2018
Subjects:
Online Access:https://eprints.nottingham.ac.uk/49552/
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author Lark, Murray
Marchant, B.P.
author_facet Lark, Murray
Marchant, B.P.
author_sort Lark, Murray
building Nottingham Research Data Repository
collection Online Access
description We use an expression for the error variance of geostatistical predictions, which includes the effect of uncertainty in the spatial covariance parameters, to examine the performance of sample designs in which a proportion of the total number of observations are distributed according to a spatial coverage design, and the remaining observations are added at supplementary close locations. This expression has been used in previous studies on numerical optimization of spatial sampling, the objective of this study was to use it to discover simple rules of thumb for practical geostatistical sampling. Results for a range of sample sizes and contrasting properties of the underlying random variables show that there is an improvement on adding just a few sample points and close pairs, and a rather slower increase in the prediction error variance as the proportion of sample points allocated in this way is increased above 10 to 20% of the total sample size. One may therefore propose a rule of thumb that, for a fixed sample size, 90% of sample sites are distributed according to a spatial coverage design, and 10% are then added at short distances from sites in the larger subset to support estimation of spatial covariance parameters.
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spelling nottingham-495522020-05-04T19:38:45Z https://eprints.nottingham.ac.uk/49552/ How should a spatial-coverage sample design for a geostatistical soil survey be supplemented to support estimation of spatial covariance parameters? Lark, Murray Marchant, B.P. We use an expression for the error variance of geostatistical predictions, which includes the effect of uncertainty in the spatial covariance parameters, to examine the performance of sample designs in which a proportion of the total number of observations are distributed according to a spatial coverage design, and the remaining observations are added at supplementary close locations. This expression has been used in previous studies on numerical optimization of spatial sampling, the objective of this study was to use it to discover simple rules of thumb for practical geostatistical sampling. Results for a range of sample sizes and contrasting properties of the underlying random variables show that there is an improvement on adding just a few sample points and close pairs, and a rather slower increase in the prediction error variance as the proportion of sample points allocated in this way is increased above 10 to 20% of the total sample size. One may therefore propose a rule of thumb that, for a fixed sample size, 90% of sample sites are distributed according to a spatial coverage design, and 10% are then added at short distances from sites in the larger subset to support estimation of spatial covariance parameters. Elsevier 2018-06-01 Article PeerReviewed Lark, Murray and Marchant, B.P. (2018) How should a spatial-coverage sample design for a geostatistical soil survey be supplemented to support estimation of spatial covariance parameters? Geoderma, 319 . pp. 89-99. ISSN 1872-6259 Spatial sampling; Prediction variance; Geostatistics https://www.sciencedirect.com/science/article/pii/S0016706117309187?via%3Dihub doi:10.1016/j.geoderma.2017.12.022 doi:10.1016/j.geoderma.2017.12.022
spellingShingle Spatial sampling; Prediction variance; Geostatistics
Lark, Murray
Marchant, B.P.
How should a spatial-coverage sample design for a geostatistical soil survey be supplemented to support estimation of spatial covariance parameters?
title How should a spatial-coverage sample design for a geostatistical soil survey be supplemented to support estimation of spatial covariance parameters?
title_full How should a spatial-coverage sample design for a geostatistical soil survey be supplemented to support estimation of spatial covariance parameters?
title_fullStr How should a spatial-coverage sample design for a geostatistical soil survey be supplemented to support estimation of spatial covariance parameters?
title_full_unstemmed How should a spatial-coverage sample design for a geostatistical soil survey be supplemented to support estimation of spatial covariance parameters?
title_short How should a spatial-coverage sample design for a geostatistical soil survey be supplemented to support estimation of spatial covariance parameters?
title_sort how should a spatial-coverage sample design for a geostatistical soil survey be supplemented to support estimation of spatial covariance parameters?
topic Spatial sampling; Prediction variance; Geostatistics
url https://eprints.nottingham.ac.uk/49552/
https://eprints.nottingham.ac.uk/49552/
https://eprints.nottingham.ac.uk/49552/