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scientifique

Large scale semi-automatic detection of forest roads from low density LiDAR data on steep terrain in Northern Spain / Convadonga Prendes in iForest, biogeosciences and forestry, vol 12 n° 4 (July 2019)  

Public [article]  iniForest, biogeosciences and forestry > vol 12 n° 4 (July 2019) . - pp 366 - 374 Titre : Large scale semi-automatic detection of forest roads from low density LiDAR data on steep terrain in Northern Spain Type de document : Article/Communication Auteurs : Convadonga Prendes, Auteur ; Sandra Bujan, Auteur ; Celestino Ordóñez, Auteur ; Elena Canga, Auteur Année de publication : 2019 Article en page(s) : pp 366 - 374 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] analyse d'image orientée objet [Termes IGN] axe médian [Termes IGN] chemin forestier [Termes IGN] classification pixellaire [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] Espagne [Termes IGN] montagne Résumé : (auteur) While forest roads are important to forest managers in terms of facilitating the exploitation of wood and timber, their role is far more multifunctional. They permit access to emergency services in the case of forest fires as well as acting as fire breaks, enhance biodiversity, and provide access to the public to enjoy recreational activities. Detailed maps of forest roads are an essential tool for better and more timely forest management and automatic/semi-automatic tools allow not only the creation of forest road databases, but also enable these to be updated. In Spain, LiDAR data for the entire national territory is freely available, and the capture of higher density data is planned in the next few years. As such, the development of a forest road detection methodology based on LiDAR data would allow maps of all forest roads to be developed and regularly updated. The general objective of this work was to establish a low density LiDAR data-based methodology for the semi-automatic detection of the centerline of forest roads on steep terrain with various types of canopy cover. Intensity and slope images were generated using the currently available LiDAR data of the study area (0.5 points m-2). Two image classification approaches were evaluated: pixel-based and object-oriented classification (OBIA). The LiDAR-derived centerlines obtained with the two approaches were compared with the real centerlines which had previously been digitized in the field. The road width, type of surface and type of vegetation cover were also recorded. The effectiveness of the two approaches was evaluated through three quality indicators: correctness, completeness and quality. In addition, the accuracy of the LiDAR-derived centerlines was also evaluated by combining GIS analysis and statistical methods. The pixel-based approach obtained higher values than OBIA for two of the three quality measures (correctness: 93% compared to 90%; and quality: 60% compared to 56%) as well as in terms of positional accuracy (± 5.5 m vs. ± 6.8 for OBIA). The results obtained in this study demonstrate that producing road maps is among the most valuable and easily attainable products of LiDAR data analysis. Numéro de notice : A2019-659 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.3832/ifor2989-012 Date de publication en ligne : 05/07/2019 En ligne : https://doi.org/10.3832/ifor2989-012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98528 [article]

Testing spatial heterogeneity in geographically weighted principal components analysis / Javier Roca-Pardiñas in International journal of geographical information science IJGIS, vol 31 n° 3-4 (March-April 2017)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 31 n° 3-4 (March-April 2017) . - pp 676 - 693 Titre : Testing spatial heterogeneity in geographically weighted principal components analysis Type de document : Article/Communication Auteurs : Javier Roca-Pardiñas, Auteur ; Celestino Ordóñez, Auteur ; Tomás R. Cotos-Yáñez, Auteur ; Rubén Pérez-Álvarez, Auteur Année de publication : 2017 Article en page(s) : pp 676 - 693 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse en composantes principales [Termes IGN] données localisées [Termes IGN] hétérogénéité spatiale [Termes IGN] interpolation par pondération de zones [Termes IGN] vecteur propre Résumé : (Auteur) We propose a method to evaluate the existence of spatial variability in the covariance structure in a geographically weighted principal components analysis (GWPCA). The method, that is extensive to locally weighted principal components analysis, is based on performing a statistical hypothesis test using the eigenvectors of the PCA scores covariance matrix. The application of the method to simulated data shows that it has a greater statistical power than the current statistical test that uses the eigenvalues of the raw data covariance matrix. Finally, the method was applied to a real problem whose objective is to find spatial distribution patterns in a set of soil pollutants. The results show the utility of GWPCA versus PCA. Numéro de notice : A2017-079 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2016.1224886 En ligne : http://dx.doi.org/10.1080/13658816.2016.1224886 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84342 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2017021	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2017022	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Validating the supporting structure of a parabolic solar collector using close range photogrammetry / Javier Roca-Pardiñas in Photogrammetric record, vol 28 n° 142 (June - August 2013)  

Public [article]  inPhotogrammetric record > vol 28 n° 142 (June - August 2013) . - pp 211 - 226 Titre : Validating the supporting structure of a parabolic solar collector using close range photogrammetry Type de document : Article/Communication Auteurs : Javier Roca-Pardiñas, Auteur ; Celestino Ordóñez, Auteur ; Silverio Garcia-Cortes, Auteur ; Antonio Bello, Auteur Année de publication : 2013 Article en page(s) : pp 211 - 226 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] capteur solaire [Termes IGN] photogrammétrie métrologique [Termes IGN] photogrammétrie terrestre Résumé : (Auteur) The optical efficiency of parabolic trough collectors depends on their geometric agreement with the parabolic profile design which, in turn, largely depends on the structure supporting the collector. A method for assessing the degree of agreement between the measured geometry and the theoretical design surface is described, which takes into account uncertainty in the point coordinates and is based on kernel smoothing and bootstrapping methods. The technique was applied to a 12 m long parabolic trough collector module with a newly designed supporting structure. The analysis revealed that there were significant differences between the estimated and theoretical surfaces in several parts of the collector. Numéro de notice : A2013-337 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/phor.12013 Date de publication en ligne : 07/06/2013 En ligne : https://doi.org/10.1111/phor.12013 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32475 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
106-2013021	RAB	Revue	Centre de documentation	En réserve L003	Disponible