Expert elicitation for the variogram

Phuong N. Truong, Gerard B.M. Heuvelink, John Paul Gosling

Research output: Contribution to conferencePaper

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 Matern 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.

Original languageEnglish
Pages251-256
Number of pages6
Publication statusPublished - 1 Jan 2012
Externally publishedYes
Event10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences 2012 - Florianopolis, Brazil
Duration: 10 Jul 201213 Jul 2012
Conference number: 10
http://spatial-accuracy.org/Accuracy2012

Conference

Conference10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences 2012
Abbreviated titleAccuracy 2012
CountryBrazil
CityFlorianopolis
Period10/07/1213/07/12
Internet address

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Keywords

  • Expert knowledge
  • Soil property map
  • Spatial variability
  • Uncertainty quantification
  • Vanogram

Cite this

Truong, P. N., Heuvelink, G. B. M., & Gosling, J. P. (2012). Expert elicitation for the variogram. 251-256. Paper presented at 10th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences 2012, Florianopolis, Brazil.