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A quantitative assessment of rockfall influence on forest structure in the Swiss Alps / Christine Moos in European Journal of Forest Research, vol 140 n° 1 (February 2021)
[article]
Titre : A quantitative assessment of rockfall influence on forest structure in the Swiss Alps Type de document : Article/Communication Auteurs : Christine Moos, Auteur ; Nora Khelidj, Auteur ; Antoine Guisan, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : pp 91 - 104 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] Alpes
[Termes IGN] croissance végétale
[Termes IGN] diamètre à hauteur de poitrine
[Termes IGN] dynamique de la végétation
[Termes IGN] éboulement
[Termes IGN] modèle de simulation
[Termes IGN] structure d'un peuplement forestier
[Termes IGN] SuisseRésumé : (auteur) Forests below rocky cliffs often play a very important role in protecting settlements against rockfall. The structure and development of these forests are expected to be substantially affected by the disturbance of the falling rocks. Knowing about this effect is important to predict the development of protection forests and consider potential effects of the falling blocks in management strategies. The goal of this study is to quantify differences in forest structure depending on rockfall activity in four different sites in the Swiss Alps. For this, we collected data on forest structure in zones of different rockfall activity and derived rockfall impact probabilities based on rockfall simulations. We assessed whether differences in forest structure and signs of rockfall disturbance could be observed between the rockfall zones. We additionally built mixed-effects models to identify the key variables explaining the forest characteristics described by diameter (DBH) and basal area (bA). The forest structure differs between the rockfall zones, however, with varying effects amongst the sites. DBH tends to decrease with increasing rockfall activity, whereas tree density appears to be little impacted by rockfall. For most sites, the number of deposited blocks and the simulated tree impact probability have a significant effect in the models along with the species, whereas for one site, hardly any effect of rockfall was found. Our results, obtained either from direct measurements or modelling, show that rockfall can locally influence the structure of forests, whereas the influence depends on the frequency and intensity of the rockfall disturbance. Impact probabilities obtained by simulations can serve as a good proxy for rockfall disturbances. Numéro de notice : A2021-256 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10342-020-01317-0 Date de publication en ligne : 18/09/2020 En ligne : https://doi.org/10.1007/s10342-020-01317-0 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97290
in European Journal of Forest Research > vol 140 n° 1 (February 2021) . - pp 91 - 104[article]Stand-scale climate change impacts on forests over large areas: transient responses and projection uncertainties / NIca Huber in Ecological Applications, vol 31 ([01/02/2021])
[article]
Titre : Stand-scale climate change impacts on forests over large areas: transient responses and projection uncertainties Type de document : Article/Communication Auteurs : NIca Huber, Auteur ; Harald Bugmann, Auteur Année de publication : 2021 Langues : Anglais (eng) Descripteur : [Termes IGN] analyse de sensibilité
[Termes IGN] changement climatique
[Termes IGN] croissance des arbres
[Termes IGN] forêt alpestre
[Termes IGN] incertitude des données
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] modèle de simulation
[Termes IGN] modèle dynamique
[Termes IGN] modélisation de la forêt
[Termes IGN] Suisse
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) The increasing impacts of climate change on forest ecosystems have triggered multiple model-based impact assessments for the future, which typically focused either on a small number of stand-scale case studies or on large scale analyses (i.e., continental to global). Therefore, substantial uncertainty remains regarding the local impacts over large areas (i.e., regions to countries), which is particularly problematic for forest management. We provide a comprehensive, high-resolution assessment of the climate change sensitivity of managed Swiss forests (~10,000 km2), which cover a wide range of environmental conditions. We used a dynamic vegetation model to project the development of typical forest stands derived from a stratification of the Third National Forest Inventory until the end of the 22nd century. Two types of simulations were conducted: one limited to using the extant local species, the other enabling immigration of potentially more climate-adapted species. Moreover, to assess the robustness of our projections, we quantified and decomposed the uncertainty in model projections resulting from the following sources: (1) climate change scenarios, (2) local site conditions, and (3) the dynamic vegetation model itself (i.e., represented by a set of model versions), an aspect hitherto rarely taken into account. The simulations showed substantial changes in basal area and species composition, with dissimilar sensitivity to climate change across and within elevation zones. Higher-elevation stands generally profited from increased temperature, but soil conditions strongly modulated this response. Low-elevation stands were increasingly subject to drought, with strong negative impacts on forest growth. Furthermore, current stand structure had a strong effect on the simulated response. The admixture of drought-tolerant species was found advisable across all elevations to mitigate future adverse climate-induced effects. The largest uncertainty in model projections was associated with climate change scenarios. Uncertainty induced by the model version was generally largest where overall simulated climate change impacts were small, thus corroborating the utility of the model for making projections into the future. Yet, the large influence of both site conditions and the model version on some of the projections indicates that uncertainty sources other than climate change scenarios need to be considered in climate change impact assessments. Numéro de notice : A2021-312 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1002/eap.2313 Date de publication en ligne : 25/02/2021 En ligne : https://doi.org/10.1002/eap.2313 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97811
in Ecological Applications > vol 31 [01/02/2021][article]From point clouds to high-fidelity models - advanced methods for image-based 3D reconstruction / Audrey Richard (2021)
Titre : From point clouds to high-fidelity models - advanced methods for image-based 3D reconstruction Type de document : Thèse/HDR Auteurs : Audrey Richard, Auteur Editeur : Zurich : Eidgenossische Technische Hochschule ETH - Ecole Polytechnique Fédérale de Zurich EPFZ Année de publication : 2021 Note générale : bibliographie
A thesis submitted to attain the degree of Doctor of Sciences of ETH ZurichLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] apprentissage profond
[Termes IGN] chaîne de traitement
[Termes IGN] classification par réseau neuronal convolutif
[Termes IGN] compréhension de l'image
[Termes IGN] démonstration de faisabilité
[Termes IGN] discrétisation spatiale
[Termes IGN] jeu de données localisées
[Termes IGN] modèle 3D de l'espace urbain
[Termes IGN] modélisation sémantique
[Termes IGN] optimisation (mathématiques)
[Termes IGN] Pays-Bas
[Termes IGN] reconstruction 3D
[Termes IGN] reconstruction d'objet
[Termes IGN] Rhénanie du Nord-Wesphalie (Allemagne)
[Termes IGN] semis de points
[Termes IGN] texturage
[Termes IGN] Zurich (Suisse)Résumé : (auteur) Capturing automatically a virtual 3D model of an object or a scene from a collection of images is a useful capability with a wide range of applications, including virtual/augmented reality, heritage preservation, consumer digital entertainment, autonomous robotics, navigation, industrial vision or metrology, and many more. Since the early days of photogrammetry and computer vision, it has been a topic of intensive research but has eluded a general solution for it. 3D modeling requires more than reconstructing a cloud of 3D points from images; it requires a high-fidelity representation whose form is often dependent on individual objects. This thesis guides you in the journey of image-based 3D reconstruction through several advanced methods that aims to push its boundaries, from precise and complete geometry to detailed appearance, using both theory with elegant mathematics and more recent breakthroughs in deep learning. To evaluate these methods, thorough experiments are conducted at scene level (and large-scale) where efficiency is of key importance, and at object level where accuracy, completeness and photorealism can be better appreciated. To show the individual potential of each of these methods, as well as the possible wide coverage in terms of applications, different scenarios are considered and serve as a proof-of-concept. Thereby, the journey starts with large-scale city modeling using aerial photography from the cities of Zürich (Switzerland), Enschede (Netherlands) and Dortmund (Germany), followed by single object completion using the synthetic dataset ShapeNet, that includes objects like cars, benches or planes that can be found in every city, to finish with the embellishment of these digital models via high-resolution texture mapping using a multi-view 3D dataset of real and synthetic objects, like for example statues and fountains that also dress the landscape of cities. Combining them together into an incremental pipeline dedicated to a specific application would require further tailoring but is quite possible. Numéro de notice : 17650 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Note de thèse : PhD : Sciences : ETH Zurich : 2021 En ligne : http://dx.doi.org/10.3929/ethz-b-000461735 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97892 Spatiotemporal patterns of urbanization during the last four decades in Switzerland and their impacts on urban heat islands / Marti Bosch Padros (2021)
Titre : Spatiotemporal patterns of urbanization during the last four decades in Switzerland and their impacts on urban heat islands Type de document : Thèse/HDR Auteurs : Marti Bosch Padros, Auteur ; Jérôme Chenal, Directeur de thèse ; Stéphane Joost, Directeur de thèse Editeur : Lausanne : Ecole Polytechnique Fédérale de Lausanne EPFL Année de publication : 2021 Importance : 145 p. Format : 21 x 30 cm Note générale : bibliographie
Thèse présentée pour l'obtention du grade de Docteur ès SciencesLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] aménagement du territoire
[Termes IGN] analyse diachronique
[Termes IGN] analyse spatio-temporelle
[Termes IGN] changement climatique
[Termes IGN] croissance urbaine
[Termes IGN] densité de population
[Termes IGN] espace vert
[Termes IGN] étalement urbain
[Termes IGN] ilot thermique urbain
[Termes IGN] modèle de simulation
[Termes IGN] modèle dynamique
[Termes IGN] occupation du sol
[Termes IGN] paysage urbain
[Termes IGN] service écosystémique
[Termes IGN] Suisse
[Termes IGN] urbanisationIndex. décimale : THESE Thèses et HDR Résumé : (auteur) Urbanization is nowadays a global phenomenon which is increasingly concentrating the world’s population in cities. In Switzerland, recent decades have seen an unprecedented loss of arable land due to urbanization, which has triggered amendments in the spatial planning laws with the aim of promoting urban densification. Nevertheless, despite remarkable efforts, the environmental impacts of distinctive urban patterns such as compact cities and urban sprawl remain poorly understood. One of the most remarkable environmental impacts of urbanization is the urban heat island effect, a phenomenon by which urban temperatures are warmer than in its rural surroundings. Central Europe, and therefore Switzerland, is among the regions in the world where temperatures are rising faster and the urban heat island effect is most prominent, which represents a central challenge for spatial planning. Most studies suggest that the urban heat island effect can be aggravated in compact cities, especially when considering the larger share of urban dwellers that are exposed to the highest temperatures. At the same time, the literature on the subject has seen a growing development of mitigation strategies, which suggest that the urban heat island effect can be significantly alleviated by an adequate planning of the building materials and urban green spaces. This doctoral dissertation intends to address the issues expressed above by performing a quantitative evaluation of the spatiotemporal patterns of urbanization in Switzerland and their impact on the urban heat island effect. To that end, the thesis adopts a landscape ecology perspective to quantify urban patterns and to spatially simulate the biophysical processes that underpin the urban heat island effect. The first article presents PyLandStats, an opensource library to compute landscape metrics in a repeatable and reproducible manner. In the second article, such a library is used to evaluate the spatiotemporal patterns of urbanization observed in the urban agglomerations of Bern, Lausanne and Zurich from 1980 to 2016. The results reveal that the outer zones of Bern and Lausanne are still undergoing diffusive urban expansion, whereas infill development is the dominant growth mode in both the inner and outer zones of Zurich. The thesis follows with the development of a spatially-explicit method to simulate urban heat mitigation using a recent model of urban cooling based on three biophysical mechanisms, namely tree shade, evapotranspiration and albedo. The study introduces an automated procedure to calibrate the parameters of the model, and shows that the proposed approach can outperform regression models based on remote sensing features. Then, in the fourth article, such an approach is applied to Lausanne in order to evaluate heat mitigation in a variety of urban greening scenarios which modify both the abundance and spatial configuration of the tree canopy cover. The simulations suggest a potential alleviation of the maximum nighttime temperatures of 2°C, which represents a major reduction of the human exposure to the urban heat island effect. Finally, a concluding chapter summarizes the main contributions of the dissertation and reviews key implications for urban planning in Switzerland. Overall, rather than prescribing urban densification as the customary strategy for spatial development, land use regulations and local plans should incorporate spatially-explicit evaluations of the ecosystem services provided by urban green spaces. Future research should extend the proposed approach to include further ecosystem services and explore trade-offs and spatially design solutions. Note de contenu : 1Urban greening scenarios for urban
heat mitigation- Introduction
2- Quantifying spatial patterns of landscapes
3- Spatiotemporal patterns of urbanization in three Swiss urban agglomerations
4- Spatially-explicit simulation of urban heat islands
6- Synthesis and outlookNuméro de notice : 28666 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/URBANISME Nature : Thèse étrangère Note de thèse : Thèse de Doctorat : Sciences : EPFL : 2021 DOI : sans En ligne : https://infoscience.epfl.ch/record/285477?ln=fr Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99863 Suivi des vignes par télédétection de proximité : le deep learning au service de l’agriculture de précision / Sami Beniaouf (2021)
Titre : Suivi des vignes par télédétection de proximité : le deep learning au service de l’agriculture de précision Type de document : Mémoire Auteurs : Sami Beniaouf, Auteur Editeur : Champs-sur-Marne : Ecole nationale des sciences géographiques ENSG Année de publication : 2021 Importance : 65 p. Format : 21 x 30 cm Note générale : bibliographie
Mémoire de Master PPMD Photogrammétrie, Positionnement et Mesure de DéformationLangues : Français (fre) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse d'image orientée objet
[Termes IGN] apprentissage profond
[Termes IGN] carte de la végétation
[Termes IGN] classification par réseau neuronal convolutif
[Termes IGN] géoréférencement
[Termes IGN] image captée par drone
[Termes IGN] maladie phytosanitaire
[Termes IGN] semis de points
[Termes IGN] surveillance de la végétation
[Termes IGN] Vaud (Suisse)
[Termes IGN] viticultureIndex. décimale : MPPMD Mémoires du mastère spécialisé Photogrammétrie, Positionnement et Mesures de Déformation Résumé : (auteur) Au cours des dernières années, les progrès rapides des techniques d'apprentissage en profondeur ont considérablement accéléré l'élan de la détection d'objets, qui constitue la base de nombreuses tâches de vision par ordinateur, telles que la segmentation d'instances, la classification d'images, le suivi d'objets et bien d'autres. Ce travail s’intéresse à l’utilisation de cette technique ainsi que la photogrammétrie terrestre et la télédétection dans le domaine de la viticulture, pour l’extraction et la cartographie d’informations physiologiques lié aux vignes. Cette étude s’est orientée vers la détection de la maladie de Mildiou au moyen d’une caméra multispectrale. Le mildiou de la vigne est causé par l'organisme de type fongique Plasmopara viticola, qui se produit généralement pendant les années excessivement humides et chaudes. Le champignon provoque directement une perte de rendement par la pourriture des feuilles, des grappes et des pousses. La détection d’objets par segmentation en instances a été réalisé en utilisant le modèle d’apprentissage pré-entraîné Mask R-CNN, dont les couches de classification ont été réentraîné avec des images de vignes acquises et labélisées. La méthodologie suivie consiste en l’extraction de masques d’objets des classes d’intérêt en utilisant le modèle entraîné, qui sont ensuite importés séparément sur les images. La reconstruction du nuage de points 3D à partir d’images masquées ensuit la génération d’un nuage de point de la classe cible. En segmentant ces nuages de points par instances, le calcul des coordonnées des barycentres de ces instances sont représentés finalement sur une carte. Note de contenu :
Introduction générale
I- Introduction à la viticulture de précision
I.1- Télédétection
I.2- Optimisation du rendement
I.3- Détection de maladies
I.4- Apprentissage profond
II- Acquisition des images et méthodologie
II.1- Acquisition des images
II.2- Méthodologie
Résultats et analyseNuméro de notice : 28393 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Mémoire PPMD Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98747 Documents numériques
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