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Detection of fallen trees in ALS point clouds using a Normalized Cut approach trained by simulation / Przemyslaw Polewski in ISPRS Journal of photogrammetry and remote sensing, vol 105 (July 2015)
[article]
Titre : Detection of fallen trees in ALS point clouds using a Normalized Cut approach trained by simulation Type de document : Article/Communication Auteurs : Przemyslaw Polewski, Auteur ; Wei Yao, Auteur ; Marco Heurich, Auteur ; Peter Krzystek, Auteur ; Uwe Stilla, Auteur Année de publication : 2015 Article en page(s) : pp 252 - 271 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] arbre mort
[Termes IGN] Bavière (Allemagne)
[Termes IGN] détection automatique
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] inventaire forestier local
[Termes IGN] parc naturel national
[Termes IGN] semis de pointsRésumé : (auteur) Downed dead wood is regarded as an important part of forest ecosystems from an ecological perspective, which drives the need for investigating its spatial distribution. Based on several studies, Airborne Laser Scanning (ALS) has proven to be a valuable remote sensing technique for obtaining such information. This paper describes a unified approach to the detection of fallen trees from ALS point clouds based on merging short segments into whole stems using the Normalized Cut algorithm. We introduce a new method of defining the segment similarity function for the clustering procedure, where the attribute weights are learned from labeled data. Based on a relationship between Normalized Cut’s similarity function and a class of regression models, we show how to learn the similarity function by training a classifier. Furthermore, we propose using an appearance-based stopping criterion for the graph cut algorithm as an alternative to the standard Normalized Cut threshold approach. We set up a virtual fallen tree generation scheme to simulate complex forest scenarios with multiple overlapping fallen stems. This simulated data is then used as a basis to learn both the similarity function and the stopping criterion for Normalized Cut. We evaluate our approach on 5 plots from the strictly protected mixed mountain forest within the Bavarian Forest National Park using reference data obtained via a manual field inventory. The experimental results show that our method is able to detect up to 90% of fallen stems in plots having 30–40% overstory cover with a correctness exceeding 80%, even in quite complex forest scenes. Moreover, the performance for feature weights trained on simulated data is competitive with the case when the weights are calculated using a grid search on the test data, which indicates that the learned similarity function and stopping criterion can generalize well on new plots. Numéro de notice : A2015-703 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2015.01.010 En ligne : https://doi.org/10.1016/j.isprsjprs.2015.01.010 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78339
in ISPRS Journal of photogrammetry and remote sensing > vol 105 (July 2015) . - pp 252 - 271[article]On strategies and automation in upgrading 2D to 3D landscape representations / Nikolas Prechtel in Cartography and Geographic Information Science, Vol 42 n° 3 (July 2015)
[article]
Titre : On strategies and automation in upgrading 2D to 3D landscape representations Type de document : Article/Communication Auteurs : Nikolas Prechtel, Auteur Année de publication : 2015 Article en page(s) : pp 244 - 258 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] cohérence des données
[Termes IGN] modèle 3D du site
[Termes IGN] rendu réaliste
[Termes IGN] Saxe (Allemagne)
[Termes IGN] système d'information géographique
[Termes IGN] Triangulated Irregular Network
[Termes IGN] universitéRésumé : (auteur) 3D scenes within all media indicate a societal preference shift toward 3D presentations. In spite of wide data availability and successful standardization efforts in 3D modeling, it is not a standard practice to offer large-scale topographic references to the end user in the form of 3D models. This motivates to propose automated strategies for the generation of closed 3D representations of a complete urban landscape, which at the same time account for capabilities of consumer-class devices. The campus of Dresden University of Technology served as a test case. The final appearance of the 3D model will be steered directly by the original geographic information system (GIS) data source. Such a “schematic model” displays source classes and attributes by nonphotorealistic rendering. A tested generic workflow can be presented, which programmatically integrates attributed 2D GIS entities and digital elevation model data, checks for compliancy with consistency rules and generates a slim geometric model. Only detailed GIS references can be considered to allow close-range visualization as needed in virtual walks. In delegating the geometric processing to automated workflows, playing room is gained for as well innovative as expressive texturing and, thus, design of the final 3D model. Numéro de notice : A2015-242 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1080/15230406.2014.987696 En ligne : https://doi.org/10.1080/15230406.2014.987696 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76240
in Cartography and Geographic Information Science > Vol 42 n° 3 (July 2015) . - pp 244 - 258[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 032-2015031 RAB Revue Centre de documentation En réserve L003 Disponible Site suitability for tree species: Is there a positive relation between a tree species’ occurrence and its growth? / Klara Dolos in European Journal of Forest Research, vol 134 n° 4 (July 2015)
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Titre : Site suitability for tree species: Is there a positive relation between a tree species’ occurrence and its growth? Type de document : Article/Communication Auteurs : Klara Dolos, Auteur ; Agnes Bauer, Auteur ; Steffen Albrecht, Auteur Année de publication : 2015 Article en page(s) : pp 609 - 621 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Abies alba
[Termes IGN] aire de répartition
[Termes IGN] Allemagne
[Termes IGN] croissance des arbres
[Termes IGN] écologie forestière
[Termes IGN] Fagus sylvatica
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] modèle de croissance végétale
[Termes IGN] Picea abies
[Termes IGN] Pinus sylvestris
[Termes IGN] répartition géographique
[Vedettes matières IGN] Inventaire forestierMots-clés libres : species distribution model Résumé : (auteur) In order to preserve forest ecosystem services under climate change, site suitability for tree species has to be re-assessed and management strategies have to be developed to adapt species composition. Thereby, it is reasonable to consider information on both site suitability estimations based on current species distribution and also stand productivity determined by tree growth. Currently, models for species distribution (SDMs) and tree growth are used to investigate the response of tree species to climate. However, both approaches were only applied separately so far. In this study, SDMs and growth models for Picea abies, Fagus sylvatica, Abies alba and Pinus sylvestris were calculated based on the German national forest inventories. We asked whether there is a positive relation between a tree species’ occurrence and its growth and what can be learned by their joint interpretation. The two approaches resulted in different patterns with respect to the considered environmental variables. Tree growth and occurrence probabilities were not positively correlated. This may be explained by the influence of forest pathogens and competition on species distribution by means of an increase in mortality. We concluded that the consideration of demographic processes as drivers of species distribution improves the reliability of estimates for site suitability and additionally provides information on productivity. Numéro de notice : A2015-278 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s10342-015-0876-0 Date de publication en ligne : 25/03/2015 En ligne : https://doi.org/10.1007/s10342-015-0876-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76397
in European Journal of Forest Research > vol 134 n° 4 (July 2015) . - pp 609 - 621[article]A geographic approach for combining social media and authoritative data towards identifying useful information for disaster management / João Porto de Albuquerque in International journal of geographical information science IJGIS, vol 29 n° 4 (April 2015)
[article]
Titre : A geographic approach for combining social media and authoritative data towards identifying useful information for disaster management Type de document : Article/Communication Auteurs : João Porto de Albuquerque, Auteur ; Benjamin Herfort, Auteur ; Alexander Brenning, Auteur ; Alexander Zipf, Auteur Année de publication : 2015 Article en page(s) : pp 667 - 689 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web
[Termes IGN] acquisition de données
[Termes IGN] Allemagne
[Termes IGN] données issues des réseaux sociaux
[Termes IGN] données localisées des bénévoles
[Termes IGN] Elbe (fleuve)
[Termes IGN] géopositionnement
[Termes IGN] gestion de crise
[Termes IGN] inondation
[Termes IGN] qualité des données
[Termes IGN] risque naturel
[Termes IGN] TwitterRésumé : (Auteur) In recent years, social media emerged as a potential resource to improve the management of crisis situations such as disasters triggered by natural hazards. Although there is a growing research body concerned with the analysis of the usage of social media during disasters, most previous work has concentrated on using social media as a stand-alone information source, whereas its combination with other information sources holds a still underexplored potential. This article presents an approach to enhance the identification of relevant messages from social media that relies upon the relations between georeferenced social media messages as Volunteered Geographic Information and geographic features of flood phenomena as derived from authoritative data (sensor data, hydrological data and digital elevation models). We apply this approach to examine the micro-blogging text messages of the Twitter platform (tweets) produced during the River Elbe Flood of June 2013 in Germany. This is performed by means of a statistical analysis aimed at identifying general spatial patterns in the occurrence of flood-related tweets that may be associated with proximity to and severity of flood events. The results show that messages near (up to 10 km) to severely flooded areas have a much higher probability of being related to floods. In this manner, we conclude that the geographic approach proposed here provides a reliable quantitative indicator of the usefulness of messages from social media by leveraging the existing knowledge about natural hazards such as floods, thus being valuable for disaster management in both crisis response and preventive monitoring. Numéro de notice : A2015-591 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2014.996567 En ligne : http://www.tandfonline.com/doi/full/10.1080/13658816.2014.996567 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77878
in International journal of geographical information science IJGIS > vol 29 n° 4 (April 2015) . - pp 667 - 689[article]Association of tree and plot characteristics with microhabitat formation in European beech and Douglas-fir forests / Susanne Winter in European Journal of Forest Research, vol 134 n° 2 (March 2015)
[article]
Titre : Association of tree and plot characteristics with microhabitat formation in European beech and Douglas-fir forests Type de document : Article/Communication Auteurs : Susanne Winter, Auteur ; Josef Höfler, Auteur ; Alexa K. Michel, Auteur Année de publication : 2015 Article en page(s) : pp 335 - 347 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] Allemagne
[Termes IGN] Etats-Unis
[Termes IGN] Fagus (genre)
[Termes IGN] habitat animal
[Termes IGN] placette d'échantillonnage
[Termes IGN] Pseudotsuga menziesiiRésumé : (auteur) Process-orientated, unmanaged forest remnants are not sufficient for halting the loss of forest biodiversity. Thus, integrated biodiversity-promoting management for forest inhabitants is needed. Microhabitats, such as tree cavities or bark pockets, are essential for the preservation of saproxylic species and of critical importance for endangered ones. This study investigates (1) which factors trigger the formation of microhabitats at both the individual tree and aggregated plot level, and (2) whether the co-occurrence of microhabitats differs between managed (=logged) and unmanaged forests. Relationships between the occurrence of 17 microhabitat types and individual tree features (e.g. light availability, and tree vitality) and plot characteristics (e.g. stand density index and stand age) in 398 plots dominated by Fagus sylvatica or Pseudotsuga menziesii in Germany and the USA were studied using random-effects logistic and normal regression modelling. Separate analyses were performed for German beech forests, German Douglas-fir forests, and the US Douglas-fir forests. Our results show that (1) tree diameter in breast height (DBH), tree vitality and branchiness or epicormic branches are highly related with the occurrence of one or more microhabitats on individual trees in managed and unmanaged beech and US Douglas-fir forests. In managed German Douglas-fir forests, vitality is not a predictor for the occurrence of microhabitats on a tree, but tree density and the maximum age of trees in a stand in addition to DBH and branchiness have an effect. Time since last management is not a statistically significant predictor for the presence of microhabitats at the tree level, but it is for German beech at the plot level. In Douglas-fir-dominated forests both in Germany and in the USA, the stand density index was the only common predictor at the plot level. (2) Unmanaged German beech and Douglas-fir forests exhibit more statistically significant and positive correlations with microhabitat groups than managed stands, implying that the presence of one microhabitat group on a tree is associated with the presence of other microhabitat groups. We finally conclude that measures for supporting microhabitat inhabitants in managed forests are scale and species dependent (tree versus plot level; beech versus Douglas-fir-dominated forests). Trees that carry microhabitats seem to have similar features independently of forest management. At the plot level, density management may trigger the accumulation of microhabitats. Our results indicate that in forest management, it is possible to consider the factors influencing the formation of microhabitats and implement adequate forest practices to advance their formation. Numéro de notice : A2015-187 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article DOI : 10.1007/s10342-014-0855-x Date de publication en ligne : 18/11/2014 En ligne : https://doi.org/10.1007/s10342-014-0855-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75957
in European Journal of Forest Research > vol 134 n° 2 (March 2015) . - pp 335 - 347[article]Persistent scatterers at building facades – Evaluation of appearance and localization accuracy / Stefan Gernhardt in ISPRS Journal of photogrammetry and remote sensing, vol 100 (February 2015)PermalinkPermalinkJonctions effectuées en 2015 entre les réseaux de nivellement français et allemand / Alain Coulomb (2015)PermalinkThe Forests in Germany / Federal ministry of food and agriculture = Bundesministerium für Ernährung und Landwirtschaft (Berlin, Allemagne) (2015)Permalink1914-1918 : les cartes à l'épreuve de la guerre / Guillaume Lebailly in Carto, le monde en cartes, n° 25 (septembre - octobre 2014)PermalinkEUPOS® – An International Initiative towards GNSS-based Positioning Infrastructure for Central and Eastern Europe / Jaroslav Simek in ZFV, Zeitschrift für Geodäsie, Geoinformation und Landmanagement, vol 139 n° 5 (September - Oktober 2014)PermalinkOpen Data: Zukunftsorientierte Bereitstellung von amtlichen Geodaten im Land Berlin / Michael Friedt in ZFV, Zeitschrift für Geodäsie, Geoinformation und Landmanagement, vol 139 n° 5 (September - Oktober 2014)PermalinkManaging Germany's big imagery data / Mladen Stojic in GEO: Geoconnexion international, vol 13 n° 2 (february 2014)PermalinkMaximum-likelihood estimation for multi-aspect multi-baseline SAR interferometry of urban areas / Michael Schmitt in ISPRS Journal of photogrammetry and remote sensing, vol 87 (January 2014)PermalinkRadargrammetric registration of airborne multi-aspect SAR data of urban areas / Michael Schmitt in ISPRS Journal of photogrammetry and remote sensing, vol 86 (December 2013)Permalink