1,721,031 research outputs found
Semis de points LiDAR aéroporté - Parc naturel régional du Massif des Bauges, partie Haute-Savoie - 2018
No full textSemis de points LiDAR - Parc naturel régional du Massif des Bauges, partie Haute-Savoie. Le levé LiDAR a été réalisé par l'entreprise Opsia pour le PNR du Massif des Bauges dans le cadre du projet PROTEST (subvention ADEME 1703C0069).
Les conditions générales de l'acquisition sont les suivantes :
Date de l'acquisition : 10-11/09/2018
Laser : Riegl LMS Q780
Les paramètres du vol LiDAR sont les suivants :
Hauteur de vol : 1050m / sol
Vitesse de vol : 160 km/h
Angle de scan : 60°
Densité moyenne d'impulsions : 13,5 impulsions / m²
Densité de points sol après classification : 6.4 point / m²
Les points sont fournis dans le système RGF93-Lambert 93 / IGN69 et triés en 5 classes : sol (2), sursol (4), eau (9), pylônes et câbles (10) et autres (1 : voitures, panneaux, etc.).
Les données sont constituées des fichiers suivants :
Plan de situation (pdf)
Rapport d'acquisition (pdf)
Tableau d'assemblage (geopackage)
Trajectographie (1 archive zip de 400 Mo contenant 3 fichiers texte)
Semis de points classés (2 archives zip totalisant 52 Go, contenant des fichiers au format LAZ, cf https://laszip.org/)
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lidaRtRee: R package for forest analysis with airborne laser scanning (LiDAR) data
No full textlidaRtRee is an R package that provides functions for forest analysis using airborne laser scanning (LiDAR remote sensing) data:
tree detection (method 1 in Eysn et al., 2015) and segmentation;
forest parameters estimation and mapping with the area-based approach.
It includes complementary steps for forest mapping:
co-registration of field plots with LiDAR data (Monnet and Mermin, 2014);
extraction of both physical (gaps, edges, trees) and statistical features from LiDAR data useful for e.g. habitat suitability modeling (Glad et al., 2020) and forest maturity mapping (Fuhr et al., 2022);
model calibration with ground reference;
maps export.
It is available on CRAN.
Tutorials are available in the documentation.lidaRtRee est un package R pour l'analyse de la structure des forêts à partir de données acquises par scanner laser (LiDAR) aéroporté :
détection d'arbres (méthode 1 dans Eysn et al., 2015) et segmentation ;
estimation de variables forestière et cartographie par approche surfacique.
Il propose des fonctions additionnelles telles que :
géoréférencement des données de terrain avec les données LiDAR (Monnet and Mermin, 2014);
extraction de statistiques et d'objets (trouées, lisières, arbres) utilisables par exemple pour la modélisation d'habitat (Glad et al., 2020) et la cartographie de la maturité des forêts (Fuhr et al., 2022);
calibration de modèles avec des données de terrrain ;
production de cartes.
Le package est disponible sur CRAN.
Des tutoriels sont disponibles dans la documentation
lidaRtRee: un package R pour l'analyse forestière avec des données LiDAR
No full textlidaRtRee provides functions for forest objects detection, structure features computation, model calibration and mapping:- co-registration of field plots with LiDAR data (Monnet and Mermin, 2014); - tree detection (method 1 in Eysn et al., 2015) and segmentation; - forest parameters estimation with the area-based approach: model calibration with ground reference, and maps export;- extraction of both physical (gaps, edges, trees) and statistical features from LiDAR data useful for e.g. habitat suitability modeling (Glad et al., 2020) or forest maturity mapping (Fuhr et al., 2022).lidaRtRee est un package R pour l'analyse de la structure des forêts à partir de données acquises par scanner laser (LiDAR) aéroporté :- détection d'arbres (méthode 1 dans Eysn et al., 2015) et segmentation ;- estimation de variables forestière et cartographie par approche surfacique.Il propose des fonctions additionnelles telles que :- géoréférencement des données de terrain avec les données LiDAR (Monnet and Mermin, 2014);- extraction de statistiques et d'objets (trouées, lisières, arbres) utilisables par exemple pour la modélisation d'habitat (Glad et al., 2020) et la cartographie de la maturité des forêts (Fuhr et al., 2022);- calibration de modèles avec des données de terrrain ;- production de cartes.Le package est disponible sur CRAN. Des tutoriels sont disponibles dans la documentation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Using airborne laser scanning for mountain forests mapping : support vector regression for stand parameters estimation and unsupervised training for treetop detection.
No full textDe nombreux travaux ont montré le potentiel de la télédétection parscanner laser aéroporté pour caractériser les massifs forestiers.Cependant, l'application aux forêts complexes de montagne reste encorepeu documentée. On se propose donc de tester les deux principalesméthodes permettant d'extraire des paramètres forestiers sur desdonnées acquises en zone montagneuse et de les adapter aux contraintesspéci fiques à cet environnement. En particulier on évaluera d'unepart l'apport conjoint de la régression à vecteurs de support et de laréduction de dimension pour l'estimation de paramètres de peuplement,et d'autre part l'intérêt d'un apprentissage non supervisé pour ladétection d'arbres.Numerous studies have shown the potential of airborne laser scanningfor the mapping of forest resources. However, the application of thisremote sensing technique to complex forests encountered in mountainousareas requires further investigation. In this thesis, the two mainmethods used to derive forest information are tested with airbornelaser scanning data acquired in the French Alps, and adapted to theconstraints of mountainous environments. In particular,a framework for unsupervised training of treetop detection isproposed, and the performance of support vector regression combinedwith dimension reduction for forest stand parameters estimation isevaluated
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