Uncertainty in mapped geological boundaries held by a national geological survey:eliciting the geologists' tacit error model

It is generally accepted that geological line work, such as mapped boundaries, are uncertain for various reasons. It is difficult to quantify this uncertainty directly, because the investigation of error in a boundary at a single location may be costly and time consuming, and many such observations...

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Main Authors: R. M. Lark, R. S. Lawley, A. J. M. Barron, D. T. Aldiss, K. Ambrose, A. H. Cooper, J. R. Lee, C. N. Waters
Format: Article
Language:English
Published: Copernicus Publications 2015-06-01
Series:Solid Earth
Online Access:http://www.solid-earth.net/6/727/2015/se-6-727-2015.pdf
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author R. M. Lark
R. S. Lawley
A. J. M. Barron
D. T. Aldiss
K. Ambrose
A. H. Cooper
J. R. Lee
C. N. Waters
author_facet R. M. Lark
R. S. Lawley
A. J. M. Barron
D. T. Aldiss
K. Ambrose
A. H. Cooper
J. R. Lee
C. N. Waters
author_sort R. M. Lark
collection DOAJ
description It is generally accepted that geological line work, such as mapped boundaries, are uncertain for various reasons. It is difficult to quantify this uncertainty directly, because the investigation of error in a boundary at a single location may be costly and time consuming, and many such observations are needed to estimate an uncertainty model with confidence. However, it is recognized across many disciplines that experts generally have a tacit model of the uncertainty of information that they produce (interpretations, diagnoses, etc.) and formal methods exist to extract this model in usable form by elicitation. In this paper we report a trial in which uncertainty models for geological boundaries mapped by geologists of the British Geological Survey (BGS) in six geological scenarios were elicited from a group of five experienced BGS geologists. In five cases a consensus distribution was obtained, which reflected both the initial individually elicited distribution and a structured process of group discussion in which individuals revised their opinions. In a sixth case a consensus was not reached. This concerned a boundary between superficial deposits where the geometry of the contact is hard to visualize. The trial showed that the geologists' tacit model of uncertainty in mapped boundaries reflects factors in addition to the cartographic error usually treated by buffering line work or in written guidance on its application. It suggests that further application of elicitation, to scenarios at an appropriate level of generalization, could be useful to provide working error models for the application and interpretation of line work.
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spelling doaj.art-543536840eb94b76a636fb894114b8e92022-12-22T01:36:26ZengCopernicus PublicationsSolid Earth1869-95101869-95292015-06-016272774510.5194/se-6-727-2015Uncertainty in mapped geological boundaries held by a national geological survey:eliciting the geologists' tacit error modelR. M. Lark0R. S. Lawley1A. J. M. Barron2D. T. Aldiss3K. Ambrose4A. H. Cooper5J. R. Lee6C. N. Waters7British Geological Survey, Keyworth, Nottingham, UKBritish Geological Survey, Keyworth, Nottingham, UKBritish Geological Survey, Keyworth, Nottingham, UKBritish Geological Survey, Keyworth, Nottingham, UKBritish Geological Survey, Keyworth, Nottingham, UKBritish Geological Survey, Keyworth, Nottingham, UKBritish Geological Survey, Keyworth, Nottingham, UKBritish Geological Survey, Keyworth, Nottingham, UKIt is generally accepted that geological line work, such as mapped boundaries, are uncertain for various reasons. It is difficult to quantify this uncertainty directly, because the investigation of error in a boundary at a single location may be costly and time consuming, and many such observations are needed to estimate an uncertainty model with confidence. However, it is recognized across many disciplines that experts generally have a tacit model of the uncertainty of information that they produce (interpretations, diagnoses, etc.) and formal methods exist to extract this model in usable form by elicitation. In this paper we report a trial in which uncertainty models for geological boundaries mapped by geologists of the British Geological Survey (BGS) in six geological scenarios were elicited from a group of five experienced BGS geologists. In five cases a consensus distribution was obtained, which reflected both the initial individually elicited distribution and a structured process of group discussion in which individuals revised their opinions. In a sixth case a consensus was not reached. This concerned a boundary between superficial deposits where the geometry of the contact is hard to visualize. The trial showed that the geologists' tacit model of uncertainty in mapped boundaries reflects factors in addition to the cartographic error usually treated by buffering line work or in written guidance on its application. It suggests that further application of elicitation, to scenarios at an appropriate level of generalization, could be useful to provide working error models for the application and interpretation of line work.http://www.solid-earth.net/6/727/2015/se-6-727-2015.pdf
spellingShingle R. M. Lark
R. S. Lawley
A. J. M. Barron
D. T. Aldiss
K. Ambrose
A. H. Cooper
J. R. Lee
C. N. Waters
Uncertainty in mapped geological boundaries held by a national geological survey:eliciting the geologists' tacit error model
Solid Earth
title Uncertainty in mapped geological boundaries held by a national geological survey:eliciting the geologists' tacit error model
title_full Uncertainty in mapped geological boundaries held by a national geological survey:eliciting the geologists' tacit error model
title_fullStr Uncertainty in mapped geological boundaries held by a national geological survey:eliciting the geologists' tacit error model
title_full_unstemmed Uncertainty in mapped geological boundaries held by a national geological survey:eliciting the geologists' tacit error model
title_short Uncertainty in mapped geological boundaries held by a national geological survey:eliciting the geologists' tacit error model
title_sort uncertainty in mapped geological boundaries held by a national geological survey eliciting the geologists tacit error model
url http://www.solid-earth.net/6/727/2015/se-6-727-2015.pdf
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