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Image processing of airborne scanning laser altimetry data for improved river flood modelling / D.M. Cobby in ISPRS Journal of photogrammetry and remote sensing, vol 56 n° 2 (December 2001 - March 2002)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 56 n° 2 (December 2001 - March 2002) . - pp 121 - 138 Titre : Image processing of airborne scanning laser altimetry data for improved river flood modelling Type de document : Article/Communication Auteurs : D.M. Cobby, Auteur ; D.C. Mason, Auteur ; Ian J. Davenport, Auteur Année de publication : 2001 Article en page(s) : pp 121 - 138 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] détection de contours [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] erreur moyenne quadratique [Termes IGN] extraction [Termes IGN] inondation [Termes IGN] modèle de simulation [Termes IGN] modèle hydrographique [Termes IGN] prévention des risques [Termes IGN] segmentation d'image [Termes IGN] télémétrie laser aéroporté Résumé : (Auteur) Airborne scanning laser altimetry (LiDAR) is an important new data source for environmental applications, being able to map topographic height, and the height of surface objects, to high vertical and horizontal accuracy over large areas. This paper describes a range image segmentation system for data from a LiDAR measuring either time of last significant return, or measuring time of both first and last returns. We focus on the application of the segmenter to improving the data required by 2D hydraulic flood models, i.e. maps of topographic height which provide model bathymetry, and vegetation height, which could be converted to distributed floodplain friction coefficients. In addition, the location of river channels and a suitable height contour are used to define the extent of the model domain. An advantage of segmentation is that it allows different topographic and vegetation height extraction algorithms to be used in regions of different cover type. LiDAR data for a reach of the River Severn, UK, is presented. Short vegetation heights (grass and cereal crops) are predicted with a rms error of 14 em. The topography underlying such cover differs from manually measured spot heights by 17 em (rms error). The topographic accuracy decreases in the presence of a densely wooded slope. Errors in the vegetation height map, apparent at the overlap regions of adjacent swaths, are reduced by the removal of heights measured at large scan angles. Copyright ISPRS Numéro de notice : A2001-208 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/S0924-2716(01)00039-9 En ligne : https://doi.org/10.1016/S0924-2716(01)00039-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21902 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-01031	SL	Revue	Centre de documentation	Revues en salle	Disponible

Application of airborne scanning laser altimetry to the study of the tidal channel geomorphology / Bharat Lohani in ISPRS Journal of photogrammetry and remote sensing, vol 56 n° 2 (December 2001 - March 2002)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 56 n° 2 (December 2001 - March 2002) . - pp 100 - 120 Titre : Application of airborne scanning laser altimetry to the study of the tidal channel geomorphology Type de document : Article/Communication Auteurs : Bharat Lohani, Auteur ; D.C. Mason, Auteur Année de publication : 2001 Article en page(s) : pp 100 - 120 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] estuaire [Termes IGN] extraction [Termes IGN] géomorphologie [Termes IGN] marée océanique [Termes IGN] marégraphie [Termes IGN] océanographie dynamique [Termes IGN] sédimentologie [Termes IGN] segmentation d'image [Termes IGN] télémétrie laser aéroporté Résumé : (Auteur) Tidal channel play a fundamental role in the hydrodynamic and morphological processes operating within a tidal basin. Conventional means of mapping intertidal zones are either too cumbersome or do not provide sufficient information for accurate quantitative measurements of the channels. This paper describes the use of the airborne scanning altimetry (light detection and ranging-LIDAR) for studying tidal channel morphology. The main emphasis is on developing a technique for extracting tidal channels from LiDAR data. Some common existing techniques of fluvial channel extraction are evaluated with LiDAR data of tidal basins and found moderate in performance. A semiautomatic approach is proposed which has a performance better than that of existing techniques. This approach is realised using an adaptative height thresholding technique to locate channel fragments. A channel joining mechanism then connects the channel fragment using weighted distance transform. The paper also describes briefly an automatic procedure to carry out measurments on the basin image and derive geomorphological parameters such as drainage density. The results obtained illustrate differences in the geomorphology of tidal and terrestrial basins. Copyright ISPRS Numéro de notice : A2001-209 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/S0924-2716(01)00041-7 En ligne : https://doi.org/10.1016/S0924-2716(01)00041-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21903 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-01031	SL	Revue	Centre de documentation	Revues en salle	Disponible