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dc.contributor.authorLiénard, Jeanen_NZ
dc.contributor.authorLynn, Kendraen_NZ
dc.contributor.authorStrigul, Nikolayen_NZ
dc.contributor.authorNorris, Benjamin K.en_NZ
dc.contributor.authorGatziolis, Demetriosen_NZ
dc.contributor.authorMullarney, Julia C.en_NZ
dc.contributor.authorBryan, Karin R.en_NZ
dc.contributor.authorHenderson, Stephen M.en_NZ
dc.date.accessioned2016-06-22T21:55:22Z
dc.date.available2016en_NZ
dc.date.available2016-06-22T21:55:22Z
dc.date.issued2016en_NZ
dc.identifier.citationLiénard, J., Lynn, K., Strigul, N., Norris, B. K., Gatziolis, D., Mullarney, J. C., … Henderson, S. M. (2016). Efficient three-dimensional reconstruction of aquatic vegetation geometry: Estimating morphological parameters influencing hydrodynamic drag. Estuarine, Coastal and Shelf Science, 178, 77–85. http://doi.org/10.1016/j.ecss.2016.05.011en
dc.identifier.issn1096-0015en_NZ
dc.identifier.urihttps://hdl.handle.net/10289/10410
dc.description.abstractAquatic vegetation can shelter coastlines from energetic waves and tidal currents, sometimes enabling accretion of fine sediments. Simulation of flow and sediment transport within submerged canopies requires quantification of vegetation geometry. However, field surveys used to determine vegetation geometry can be limited by the time required to obtain conventional caliper and ruler measurements. Building on recent progress in photogrammetry and computer vision, we present a method for reconstructing three-dimensional canopy geometry. The method was used to survey a dense canopy of aerial mangrove roots, called pneumatophores, in Vietnam’s Mekong River Delta. Photogrammetric estimation of geometry required 1) taking numerous photographs at low tide from multiple viewpoints around 1 m2 quadrats, 2) computing relative camera locations and orientations by triangulation of key features present in multiple images and reconstructing a dense 3D point cloud, and 3) extracting pneumatophore locations and diameters from the point cloud data. Step 3) was accomplished by a new ‘sector-slice’ algorithm, yielding geometric parameters every 5 mm along a vertical profile. Photogrammetric analysis was compared with manual caliper measurements. In all 5 quadrats considered, agreement was found between manual and photogrammetric estimates of stem number, and of number × mean diameter, which is a key parameter appearing in hydrodynamic models. In two quadrats, pneumatophores were encrusted with numerous barnacles, generating a complex geometry not resolved by hand measurements. In remaining cases, moderate agreement between manual and photogrammetric estimates of stem diameter and solid volume fraction was found. By substantially reducing measurement time in the field while capturing in greater detail the 3D structure, photogrammetry has potential to improve input to hydrodynamic models, particularly for simulations of flow through large-scale, heterogenous canopies.en_NZ
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherElsevieren_NZ
dc.relation.urihttp://www.sciencedirect.com/science/article/pii/S0272771416301482en_NZ
dc.rightsThis is an author’s accepted version of an article published in the journal: Estuarine, Coastal and Shelf Science. © 2016 Elsevier.
dc.subjectdrag coefficienten_NZ
dc.subjectphotogrammetryen_NZ
dc.subjectmangroveen_NZ
dc.subjectestuariesen_NZ
dc.subjectemergent vegetationen_NZ
dc.subjectplant morphologyen_NZ
dc.titleEfficient three-dimensional reconstruction of aquatic vegetation geometry: Estimating morphological parameters influencing hydrodynamic dragen_NZ
dc.typeJournal Article
dc.identifier.doi10.1016/j.ecss.2016.05.011en_NZ
dc.relation.isPartOfEstuarine, Coastal and Shelf Scienceen_NZ
pubs.begin-page77
pubs.elements-id139362
pubs.end-page85
pubs.notesEBSCOhost confirms peer rervieweden_NZ
pubs.organisational-group/Waikato
pubs.organisational-group/Waikato/FSEN
pubs.organisational-group/Waikato/FSEN/School of Science
pubs.volume178en_NZ
uow.identifier.article-noCen_NZ


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