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The willingness of volonteers to report changes on topographic maps / Mihaela Triglav Cekada in Geodetski vestnik, vol 65 n° 3 (September - November 2021)  

Public [article]  inGeodetski vestnik > vol 65 n° 3 (September - November 2021) Titre : The willingness of volonteers to report changes on topographic maps Type de document : Article/Communication Auteurs : Mihaela Triglav Cekada, Auteur ; Dalibor Radovan, Auteur Année de publication : 2021 Langues : Anglais (eng) Slovène (slv) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] approche participative [Termes IGN] carte topographique [Termes IGN] collecte de données [Termes IGN] données localisées des bénévoles [Termes IGN] enquête [Termes IGN] fiabilité des données [Termes IGN] mise à jour cartographique [Termes IGN] questionnaire [Termes IGN] réseau social [Termes IGN] Slovénie Résumé : (auteur) Various possibilities for collecting volunteer-provided geographical information in geodesy make it possible to engage volunteers for different purposes. In this paper, a study of the willingness of volunteers to report changes on topographic maps based on an online survey is presented. The survey was answered by 653 Slovenian respondents who use various online or classic topographic maps in their free time or at work and are willing to report their knowledge of changes in space or errors in maps to the map-updating institution. The survey's main finding is that 56% of respondents would use any online application to report changes on maps, 38% of respondents would prefer to report changes via email, and only 4% of respondents would prefer to report changes by phone. We also analysed the potential use of different functionalities of a web application for collecting changes and found that the most important functionalities for volunteers are those that give the most in-depth feedback (i.e., that a contribution has been submitted, that it is being verified, that it has been considered, that it has been deleted). The willingness of potential volunteers to use the various proposed functionalities also frequently depends on their current involvement with social networking sites or in volunteer associations and on their age group. Numéro de notice : A2021-771 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.15292/geodetski-vestnik.2021.03.400-439 Date de publication en ligne : 18/07/2021 En ligne : https://doi.org/10.15292/geodetski-vestnik.2021.03.400-439 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98825 [article]

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Predicting tree species based on the geometry and density of aerial laser scanning point cloud of treetops / Nina Kranjec in Geodetski vestnik, vol 65 n° 2 (June - August 2021)  

Public [article]  inGeodetski vestnik > vol 65 n° 2 (June - August 2021) . - pp 234 - 259 Titre : Predicting tree species based on the geometry and density of aerial laser scanning point cloud of treetops Type de document : Article/Communication Auteurs : Nina Kranjec, Auteur ; Mihaela Triglav Cekada, Auteur ; Milan Kobal, Auteur Année de publication : 2021 Article en page(s) : pp 234 - 259 Note générale : bibliographie Langues : Anglais (eng) Slovène (slv) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] Acer pseudoplatanus [Termes IGN] apprentissage automatique [Termes IGN] arbre de décision [Termes IGN] densité des points [Termes IGN] données lidar [Termes IGN] Fagus sylvatica [Termes IGN] feuillu [Termes IGN] figure géométrique [Termes IGN] Fraxinus excelsior [Termes IGN] houppier [Termes IGN] identification automatique [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] Larix decidua [Termes IGN] modèle de simulation [Termes IGN] modèle numérique de surface de la canopée [Termes IGN] Picea abies [Termes IGN] Pinophyta [Termes IGN] Pinus sylvestris [Termes IGN] semis de points [Termes IGN] Slovénie Résumé : (auteur) Based on the laser point clouds of 240 individual trees that were also identified in the field, we developed decision trees to distinguish deciduous and coniferous trees and individual tree species: Picea abies, Larix decidua, Pinus sylvestris, Fagus sylvatica, Acer pseudoplatanus, Fraxinus excelsior. The volume of the upper part of the tree crown (height of 3 m) and the average intensity of the laser reflections were used as explanatory variables. There were four aerial laser datasets: May 2012, September 2012, March 2013 and July 2015. We found that the combination of the volume and the average intensity of the first three laser datasets was the most reliable for predicting the selected tree species (60% model performance). A slightly poorer model performance was obtained if only the average intensity of the first three datasets was used (54% model performance). The worst model performance was given by the intensities (31 % model performance) or the volumes (21 % model performance) of dataset 4, which represents the national laser scanning of Slovenia (LSS). The best performing was the deciduous and coniferous separation, which achieved 75% and 95% success based on the test data (combination of volume and average intensity of the first three laser datasets). Using only the LSS intensities, deciduous and coniferous trees could be separated with 81% success. Numéro de notice : A2021-559 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.15292/geodetski-vestnik.2021.02.234-259 Date de publication en ligne : 27/05/2021 En ligne : https://doi.org/10.15292/geodetski-vestnik.2021.02.234-259 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98113 [article]

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Acquisition of the 3D boundary of the Triglav glacier from archived non-metric panoramic images / Mihaela Triglav Cekada in Photogrammetric record, vol 26 n° 133 (March - May 2011)  

Public [article]  inPhotogrammetric record > vol 26 n° 133 (March - May 2011) . - pp 111 - 129 Titre : Acquisition of the 3D boundary of the Triglav glacier from archived non-metric panoramic images Type de document : Article/Communication Auteurs : Mihaela Triglav Cekada, Auteur ; R. Radovanovic, Auteur ; Dalibor Radovan, Auteur ; M. Gabrovec, Auteur ; Mojca Kosmatin-Fras, Auteur Année de publication : 2011 Article en page(s) : pp 111 - 129 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] alpes orientales [Termes IGN] analyse diachronique [Termes IGN] angle vertical [Termes IGN] chambre non métrique [Termes IGN] chambre panoramique [Termes IGN] données localisées 3D [Termes IGN] glacier [Termes IGN] modèle numérique de surface [Termes IGN] montagne [Termes IGN] numérisation de photographie [Termes IGN] photographie argentique [Termes IGN] Slovénie [Termes IGN] volume (grandeur) Résumé : (Auteur) A panoramic, non-metric, Horizont camera has been used for regular, monthly, close-range photography of the rapidly retreating Triglav glacier in Slovenia since 1976. The unfavourable geometry of the convergent images taken from the two camera stations has made any direct stereoscopic observation and recording impossible. The aim of this research was to define the most useful method for acquiring 3D data from these panoramic, convergent images. The Horizont camera was calibrated and three methods were then tested: the generation of pseudo-orthophotographs, the application of 2D clinometry and the interactive orientation of a detailed digital elevation model (DEM) on the images. The third turned out to be the only method suitable for determining the boundary of the Triglav glacier. The interactive orientation of a detailed DEM on the Horizont images is described in detail. The 3D glacier boundary can be acquired from individual Horizont images (camera stations A and B) enabling the computation of the glacier’s area and theoretical volume. By repeating the glacier boundary acquisition for different orientation parameters, the standard deviations of the glacier area and theoretical volume were computed. Because of the more precise average area and volume measurements achieved with the camera station B images, only these were chosen for the glacier disappearance study. Every third year between 1976 and 2005 the Horizont images were used to compute the changes in the area and volume of the glacier. The glacier area was found to have reduced to 8% of its earlier size, from 15 ha in 1976 to 1·2 ha in 2000. However, owing to harsher than average winters since then the decline in the glacier area was found to have slowed in the past decade (2000 to 2009). The glacier’s theoretical volume decreased roughly exponentially from 1976 to 2005 Numéro de notice : A2011-079 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.2011.00622.x Date de publication en ligne : 16/03/2011 En ligne : https://doi.org/10.1111/j.1477-9730.2011.00622.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30860 [article]

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A simplified analytical model for a-priori Lidar pointpositioning error estimation and a review of Lidar error source / Mihaela Triglav Cekada in Photogrammetric Engineering & Remote Sensing, PERS, vol 75 n° 12 (December 2009)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 75 n° 12 (December 2009) . - pp 1425 - 1439 Titre : A simplified analytical model for a-priori Lidar pointpositioning error estimation and a review of Lidar error source Type de document : Article/Communication Auteurs : Mihaela Triglav Cekada, Auteur ; F. Crosilla, Auteur ; Mojca Kosmatin-Fras, Auteur Année de publication : 2009 Article en page(s) : pp 1425 - 1439 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] données lidar [Termes IGN] erreur de positionnement [Termes IGN] erreur systématique [Termes IGN] modèle d'erreur [Termes IGN] qualité des données [Termes IGN] source d'erreur Résumé : (Auteur) Although various rigorous lidar error models already exist and examples of a-posteriori studies of lidar data accuracies verified with field-work can be found in the literature, a simple measure to define a-priori error sizes is not available. In this paper, the lidar error contributions are described in detail: the basic systematic error sources, the flight-mission-related error sources, and the target-characteristic-related error sources. A review of the different error-source sizes is drawn from the literature in order to define the boundary conditions for each error size. Schenk’s geolocation equation is used as a basis for deriving a simplified error model. This model enables a quick calculation and gives a-priori plausible values for the average and maximum error size, independent of the scan and heading angles as well as being independent of any specific lidar system’s characteristics. Additionally, some notes are provided for assistance when ordering lidar data, to enable easier a-posteriori quality control. Copyright ASPRS Numéro de notice : A2009-501 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.75.12.1425 En ligne : https://doi.org/10.14358/PERS.75.12.1425 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30130 [article]

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