Centre de documentation
scientifique

Modelling flow routing in permafrost landscapes with TWI: an evaluation against site-specific wetness measurements / A. Persson in Transactions in GIS, vol 16 n° 5 (October 2012)  

Public [article]  inTransactions in GIS > vol 16 n° 5 (October 2012) . - pp 701 - 713 Titre : Modelling flow routing in permafrost landscapes with TWI: an evaluation against site-specific wetness measurements Type de document : Article/Communication Auteurs : A. Persson, Auteur ; A. Hasan, Auteur ; J. Tang, Auteur ; Petter Pilesjö, Auteur Année de publication : 2012 Article en page(s) : pp 701 - 713 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] changement climatique [Termes IGN] dégel [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] humidité du sol [Termes IGN] modèle numérique de surface [Termes IGN] pergélisol [Termes IGN] Suède [Termes IGN] tourbe Résumé : (Auteur) In northern peatlands the thawing of permafrost increasing the active layer depth and changing the hydrology may lead to feedbacks in the climate system through changes in the biogeochemistry of carbon. We are examining this association on the Stordalen peatland complex in subarctic Sweden by analyzing a DEM derived from LiDAR-data and the calculated TWI [Topographical Wetness Index]. The DEM, with a spatial resolution of 1 m, and the TWI are evaluated against two seasons of water level measurements from 30 sites in the peatland. The TWI is calculated with a form-based flow routing algorithm which produces a natural flow routing pattern. In permafrost wetlands the topography is the major driver and is very important even though its magnitude is low. Site-specific wetness (SSW) measurements from the sites were compared with the different peatland types that occur in the study area, i.e. fen, internal fen and palsa. The results showed a strong correlation between the TWI and the palsa. The TWI was better at describing general patterns than site-specific hydrology. The evaluation of spatial patterns of TWI against SSW reveal the resolution required to develop the technique to be useful for climate change studies. Numéro de notice : A2012-520 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01338.x Date de publication en ligne : 22/08/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01338.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31966 [article]

Species identification of individual trees by combining high resolution LiDAR data with multi-spectral images / Johan Holmgren in International Journal of Remote Sensing IJRS, vol 29 n° 5 (March 2008)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 29 n° 5 (March 2008) . - pp 1537 - 1552 Titre : Species identification of individual trees by combining high resolution LiDAR data with multi-spectral images Type de document : Article/Communication Auteurs : Johan Holmgren, Auteur ; A. Persson, Auteur ; U. Sodermans, Auteur Année de publication : 2008 Article en page(s) : pp 1537 - 1552 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] analyse discriminante [Termes IGN] données lidar [Termes IGN] flore locale [Termes IGN] houppier [Termes IGN] identification automatique [Termes IGN] image multibande [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] Picea abies [Termes IGN] Pinus sylvestris [Termes IGN] Suède [Termes IGN] sylviculture [Termes IGN] traitement du signal Résumé : (Auteur) The objectives of this study were to identify useful predictive factors for tree species identification of individual trees and to compare classifications based on a combination of LiDAR data and multi-spectral images with classification by the use of each individual data source. Crown segments derived from LiDAR data were mapped to multi-spectral images for extraction of spectral data within individual tree crowns. Several features, related to height distribution of laser returns in the canopy, canopy shape, proportion of different types of laser returns, and intensity of laser returns, were derived from LiDAR data. Data from a test site in southern Sweden were used (lat. 58°30' N, long. 13°40' E). The forest consisted of Norway spruce (Picea abies), Scots pine (Pinus sylvestris), and deciduous trees. Classification into these three tree species groups was validated for 1711 trees that had been detected in LiDAR data within 14 field plots (sizes of 20x50 m or 80x80 m). The LiDAR data were acquired by the TopEye MkII system (50 LiDAR measurements per m) and the multi-spectral images were taken by the Zeiss/Intergraph Digital Mapping Camera. The overall classification accuracy was 96% when both data sources were combined. Copyright Taylor & Francis Numéro de notice : A2008-083 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160701736471 En ligne : https://doi.org/10.1080/01431160701736471 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29078 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-08031	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt

Accuracy of 3D city models: EuroSDR comparison / Harri Kaartinen (2005)  

Public Titre : Accuracy of 3D city models: EuroSDR comparison Type de document : Article/Communication Auteurs : Harri Kaartinen, Auteur ; Juha Hyyppä, Auteur ; Eberhard Gülch, Auteur ; M. George Vosselman, Auteur ; H. Hyyppä, Auteur ; Leena Matikainen, Auteur ; A.D. Hofmann, Auteur ; U. Mäder, Auteur ; A. Persson, Auteur ; U. Söderman, Auteur ; M. Elmqvist, Auteur ; A. Ruiz, Auteur ; M. Dragoja, Auteur ; David Flamanc , Auteur ; Grégoire Maillet , Auteur ; et al., Auteur Editeur : International Society for Photogrammetry and Remote Sensing ISPRS Année de publication : 2005 Collection : International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences, ISSN 1682-1750 num. 36-3/W19 Conférence : ISPRS 2005, Workshop Laser scanning 12/09/2005 14/09/2005 Enschede Pays-Bas OA Proceedings archives Importance : pp 227 - 232 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] analyse comparative [Termes IGN] modèle 3D de l'espace urbain [Termes IGN] précision des données Résumé : (auteur) The paper focuses on comparing accuracies obtained with photogrammetry and laser scanning in building extraction and partly compares results obtained with various methods. The objective of the EuroSDR Building Extraction comparison was to evaluate the quality, accuracy, feasibility and economical aspects of semi-automatic building extraction based on photogrammetric techniques with the emphasis on commercial and/or operative systems, semi-automatic and automatic building extraction techniques based on high density laser scanner data and semi-automatic and automatic building extraction techniques based on integration of laser scanner data and aerial images (hybrid technique). The project consists of three test sites by Finnish Geodetic Institute (FGI), namely Senaatti, Hermanni and Espoonlahti and one test site by Institut Geographique National (IGN), namely Amiens. For each test site following data was provided to the partners: aerial images, camera calibration and image orientation information, ground control point coordinates and jpg images of point locations (not for Amiens), laser scanner data and cadastral map vectors of selected buildings. Participants were requested to create the vectors of 3D city models. 3D-models were obtained from 11 participants. Paper confirms with experiments that laser scanning is more suitable in deriving building heights, extracting planar roof faces and ridges of the roof whereas the photogrammetry and aerial images are more suitable in building outline and length determination. CyberCity, Stuttgart and TerraScan (performed by ICC) solutions provided the highest accuracy. There seemed to be a higher variation in the quality of other models depending on test site or remotely sensed information. Numéro de notice : C2005-050 Affiliation des auteurs : MATIS+Ext (1993-2011) Thématique : IMAGERIE/INFORMATIQUE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans En ligne : https://www.isprs.org/proceedings/XXXVI/3-W19/papers/227.pdf Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103460

EuroSDR building extraction comparaison / Harri Kaartinen (2005)  

Public Titre : EuroSDR building extraction comparaison Type de document : Article/Communication Auteurs : Harri Kaartinen, Auteur ; Juha Hyyppä, Auteur ; Eberhard Gülch, Auteur ; H. Hyyppä, Auteur ; Leena Matikainen, Auteur ; M. George Vosselman, Auteur ; A.D. Hofmann, Auteur ; U. Mäder, Auteur ; A. Persson, Auteur ; U. Söderman, Auteur ; M. Elmqvist, Auteur ; A. Ruiz, Auteur ; M. Dragoja, Auteur ; David Flamanc , Auteur ; Grégoire Maillet , Auteur ; et al., Auteur Editeur : International Society for Photogrammetry and Remote Sensing ISPRS Année de publication : 2005 Collection : International Archives of Photogrammetry and Remote Sensing, ISSN 0252-8231 num. 36-1/W3 Conférence : ISPRS 2005, WG I/5, IV/3, I/1, I/3, IV/2 ISPRS Hannover Workshop 2005 High-Resolution Earth Imaging for Geospatial Information 17/05/2005 20/05/2005 Hannovre Allemagne OA ISPRS Archives Importance : 6 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] analyse comparative [Termes IGN] arc [Termes IGN] bâtiment [Termes IGN] détection du bâti [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] étalonnage de chambre métrique [Termes IGN] modèle 3D de l'espace urbain [Termes IGN] orientation d'image [Termes IGN] orthoimage [Termes IGN] point d'appui [Termes IGN] semis de points Résumé : (auteur) The paper focuses on comparing accuracies obtained with photogrammetry and laser scanning in building extraction. The objective of the EuroSDR Building Extraction comparison was to evaluate the quality, accuracy, feasibility and economical aspects of semi automatic building extraction based on photogrammetric techniques with the emphasis on commercial and/or operative systems, semi-automatic and automatic building extraction techniques based on high density laser scanner data and semi-automatic and automatic building extraction techniques based on integration of laser scanner data and aerial images. The project consists of three test sites by the Finnish Geodetic Institute (FGI), namely Senaatti, Hermanni and Espoonlahti, and one test site by the Institut Geographique National (IGN), namely Amiens. For each test site following data was provided to the partners: aerial images, camera calibration and image orientation information, ground control point coordinates and jpg images of point locations (not for Amiens), laser scanner data and cadastral map vectors of selected buildings. Participants were requested to create vectors of 3D city models. 3D-models were obtained from 11 participants. The paper confirms with experiments that laser scanning is superior in deriving building heights, extracting planar roof faces and ridges of the roof, whereas photogrammetry and aerial images are superior in building outline and length determination. Numéro de notice : C2005-037 Affiliation des auteurs : MATIS+Ext (1993-2011) Thématique : IMAGERIE/INFORMATIQUE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans En ligne : https://www.isprs.org/proceedings/XXXVI/1-W3/PDF/064-kaartinen.pdf Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100078

Detecting and measuring individual trees using an airborne laser scanner / A. Persson in Photogrammetric Engineering & Remote Sensing, PERS, vol 68 n° 9 (September 2002)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 68 n° 9 (September 2002) . - pp 925 - 932 Titre : Detecting and measuring individual trees using an airborne laser scanner Type de document : Article/Communication Auteurs : A. Persson, Auteur ; Johan Holmgren, Auteur Année de publication : 2002 Article en page(s) : pp 925 - 932 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] arbre (flore) [Termes IGN] contour [Termes IGN] données lidar [Termes IGN] erreur moyenne quadratique [Termes IGN] forêt [Termes IGN] houppier [Termes IGN] télémétrie laser aéroporté [Termes IGN] tronc Résumé : (Auteur) High-resolution airborne laser scanner data offer the possibility to detect and measure individual trees. In this study, an algorithm which estimated position, height, and crown diameter of individual trees was validated with field measurements. Because all the trees in this study were measured on the ground with high accuracy, their positions could be linked with laser measurements, making validation on an individual tree basis possible. In total, 71 percent of the trees were correctly detected using laser scanner data. Because a large portion of the undetected trees had a small stem diameter, 91 percent of the total stem volume was detected. Height and crown diameter of detected trees could be estimated with a root-mean-square error (RMSE) of 0,63 m and 0,61 m, respectively. Stem diameter was estimated, using laser measured tree height and crown diameter, with an RMSE of 3,8 cm. Different laser beam diameters (0,26 to 3,68 m) were also tested, the smallest beam size showing a better detection rate in dense forest. However, estimates of tree height and crown diameter were not affected much by different beam size. Copyright ASPRS Numéro de notice : A2002-323 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : sans En ligne : https://www.asprs.org/wp-content/uploads/pers/2002journal/september/2002_sep_925 [...] Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22234 [article]