Longitudinal subglacial bedform semi-automated mapping and measurement
This thesis addresses methodological issues in the morphometric inventorying of relict drumlins and mega-scale glacial lineations (longitudinal subglacial bedforms, LSBs) which pose limits to a robust description of LSB morphometry and thus to testing hypotheses of LSB genesis, with implications for...
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ftsimonfu:oai:summit.sfu.ca:16514 2023-05-15T16:40:48+02:00 Longitudinal subglacial bedform semi-automated mapping and measurement Gaspar Jorge, Marco André 2015-05-25 http://summit.sfu.ca/item/16514 unknown etd9025 http://summit.sfu.ca/item/16514 Thesis 2015 ftsimonfu 2022-04-07T18:40:34Z This thesis addresses methodological issues in the morphometric inventorying of relict drumlins and mega-scale glacial lineations (longitudinal subglacial bedforms, LSBs) which pose limits to a robust description of LSB morphometry and thus to testing hypotheses of LSB genesis, with implications for postdicting past, and predicting future, ice sheet behavior. Focus is on a) the adequacy of previously used morphometric measurement methods (MMM) (GIS) and b) the development of LSB semi-automated mapping (SAM) methods. Dimensions derived from an ellipse fitted to the LSB footprint based on Euler’s approximation are inaccurate and both these and orientation based on the longest straight line enclosed by the footprint are imprecise. A newly tested MMM based on the standard deviational ellipse performs best. A new SAM method outperforms previous methods. It is based on the analysis of normalized local relief closed contours and on a supervised ruleset encapsulating expert knowledge, published morphometric data and study area LSB morphometry. Thesis Ice Sheet Summit - SFU Research Repository (Simon Fraser University) |
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Summit - SFU Research Repository (Simon Fraser University) |
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description |
This thesis addresses methodological issues in the morphometric inventorying of relict drumlins and mega-scale glacial lineations (longitudinal subglacial bedforms, LSBs) which pose limits to a robust description of LSB morphometry and thus to testing hypotheses of LSB genesis, with implications for postdicting past, and predicting future, ice sheet behavior. Focus is on a) the adequacy of previously used morphometric measurement methods (MMM) (GIS) and b) the development of LSB semi-automated mapping (SAM) methods. Dimensions derived from an ellipse fitted to the LSB footprint based on Euler’s approximation are inaccurate and both these and orientation based on the longest straight line enclosed by the footprint are imprecise. A newly tested MMM based on the standard deviational ellipse performs best. A new SAM method outperforms previous methods. It is based on the analysis of normalized local relief closed contours and on a supervised ruleset encapsulating expert knowledge, published morphometric data and study area LSB morphometry. |
format |
Thesis |
author |
Gaspar Jorge, Marco André |
spellingShingle |
Gaspar Jorge, Marco André Longitudinal subglacial bedform semi-automated mapping and measurement |
author_facet |
Gaspar Jorge, Marco André |
author_sort |
Gaspar Jorge, Marco André |
title |
Longitudinal subglacial bedform semi-automated mapping and measurement |
title_short |
Longitudinal subglacial bedform semi-automated mapping and measurement |
title_full |
Longitudinal subglacial bedform semi-automated mapping and measurement |
title_fullStr |
Longitudinal subglacial bedform semi-automated mapping and measurement |
title_full_unstemmed |
Longitudinal subglacial bedform semi-automated mapping and measurement |
title_sort |
longitudinal subglacial bedform semi-automated mapping and measurement |
publishDate |
2015 |
url |
http://summit.sfu.ca/item/16514 |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_relation |
etd9025 http://summit.sfu.ca/item/16514 |
_version_ |
1766031223514202112 |