Expert elicitation for the variogram

N.P. Truong, G.B.M. Heuvelink, J.P. Gosling

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademic

Abstract

The variogram is the keystone of Kriging. Much research has been devoted to modelling the variogram from structural analysis of observations. However, there are many instances when the variogram is needed and there are no observations to base on. This can be due to budget constraints, physical or temporal obstacles, or a demand for a priori variogram in Bayesian geostatistics and spatial sampling design. Using expert knowledge that is elicited with a formal statistical expert elicitation procedure is suggested. In this study, we designed a protocol for a wellstructured elicitation procedure to elicit the variogram from expert knowledge. The protocol has two main stages: elicitation of the marginal probability distribution and elicitation of the variogram. We built a web-based tool to facilitate the procedure. A case study was carried out to quantify spatial accuracy of a legacy map of the volumetric soil water content at field capacity. Expert elicitation returns a variogram that has a Matérn model shape with nugget = 0.45, partial sill = 54.57, range = 25410 meters and kappa = 0.40. The results show that the online elicitation tool satisfactorily captured expert opinion although, currently, it is only a prototype that needs to be further developed.
LanguageEnglish
Title of host publicationProceedings of the 10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences, 10-13 July 2012, Florianopolos, Brazil
EditorsC. Vieira, V. Bogorny, A. Ribeiro Aquino
PublisherFederal University of Santa Catarina
Pages251-256
Publication statusPublished - 2012
Event10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental SciencesFlorianopolos, SC, Brazil -
Duration: 10 Jul 201213 Jul 2012

Conference

Conference10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental SciencesFlorianopolos, SC, Brazil
Period10/07/1213/07/12

Fingerprint

variogram
field capacity
geostatistics
structural analysis
kriging
sill
soil water
water content
sampling
modeling

Cite this

Truong, N. P., Heuvelink, G. B. M., & Gosling, J. P. (2012). Expert elicitation for the variogram. In C. Vieira, V. Bogorny, & A. Ribeiro Aquino (Eds.), Proceedings of the 10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences, 10-13 July 2012, Florianopolos, Brazil (pp. 251-256). Federal University of Santa Catarina.
Truong, N.P. ; Heuvelink, G.B.M. ; Gosling, J.P. / Expert elicitation for the variogram. Proceedings of the 10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences, 10-13 July 2012, Florianopolos, Brazil. editor / C. Vieira ; V. Bogorny ; A. Ribeiro Aquino. Federal University of Santa Catarina, 2012. pp. 251-256
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Truong, NP, Heuvelink, GBM & Gosling, JP 2012, Expert elicitation for the variogram. in C Vieira, V Bogorny & A Ribeiro Aquino (eds), Proceedings of the 10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences, 10-13 July 2012, Florianopolos, Brazil. Federal University of Santa Catarina, pp. 251-256, 10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental SciencesFlorianopolos, SC, Brazil, 10/07/12.

Expert elicitation for the variogram. / Truong, N.P.; Heuvelink, G.B.M.; Gosling, J.P.

Proceedings of the 10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences, 10-13 July 2012, Florianopolos, Brazil. ed. / C. Vieira; V. Bogorny; A. Ribeiro Aquino. Federal University of Santa Catarina, 2012. p. 251-256.

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademic

TY - GEN

T1 - Expert elicitation for the variogram

AU - Truong, N.P.

AU - Heuvelink, G.B.M.

AU - Gosling, J.P.

PY - 2012

Y1 - 2012

N2 - The variogram is the keystone of Kriging. Much research has been devoted to modelling the variogram from structural analysis of observations. However, there are many instances when the variogram is needed and there are no observations to base on. This can be due to budget constraints, physical or temporal obstacles, or a demand for a priori variogram in Bayesian geostatistics and spatial sampling design. Using expert knowledge that is elicited with a formal statistical expert elicitation procedure is suggested. In this study, we designed a protocol for a wellstructured elicitation procedure to elicit the variogram from expert knowledge. The protocol has two main stages: elicitation of the marginal probability distribution and elicitation of the variogram. We built a web-based tool to facilitate the procedure. A case study was carried out to quantify spatial accuracy of a legacy map of the volumetric soil water content at field capacity. Expert elicitation returns a variogram that has a Matérn model shape with nugget = 0.45, partial sill = 54.57, range = 25410 meters and kappa = 0.40. The results show that the online elicitation tool satisfactorily captured expert opinion although, currently, it is only a prototype that needs to be further developed.

AB - The variogram is the keystone of Kriging. Much research has been devoted to modelling the variogram from structural analysis of observations. However, there are many instances when the variogram is needed and there are no observations to base on. This can be due to budget constraints, physical or temporal obstacles, or a demand for a priori variogram in Bayesian geostatistics and spatial sampling design. Using expert knowledge that is elicited with a formal statistical expert elicitation procedure is suggested. In this study, we designed a protocol for a wellstructured elicitation procedure to elicit the variogram from expert knowledge. The protocol has two main stages: elicitation of the marginal probability distribution and elicitation of the variogram. We built a web-based tool to facilitate the procedure. A case study was carried out to quantify spatial accuracy of a legacy map of the volumetric soil water content at field capacity. Expert elicitation returns a variogram that has a Matérn model shape with nugget = 0.45, partial sill = 54.57, range = 25410 meters and kappa = 0.40. The results show that the online elicitation tool satisfactorily captured expert opinion although, currently, it is only a prototype that needs to be further developed.

M3 - Conference contribution

SP - 251

EP - 256

BT - Proceedings of the 10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences, 10-13 July 2012, Florianopolos, Brazil

A2 - Vieira, C.

A2 - Bogorny, V.

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PB - Federal University of Santa Catarina

ER -

Truong NP, Heuvelink GBM, Gosling JP. Expert elicitation for the variogram. In Vieira C, Bogorny V, Ribeiro Aquino A, editors, Proceedings of the 10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences, 10-13 July 2012, Florianopolos, Brazil. Federal University of Santa Catarina. 2012. p. 251-256