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#Earthquake: Twitter as a distributed sensor system / Andrew Crooks in Transactions in GIS, vol 17 n° 1 (February 2013)
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Titre : #Earthquake: Twitter as a distributed sensor system Type de document : Article/Communication Auteurs : Andrew Crooks, Auteur ; Arie Croitoru, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 124 - 147 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web
[Termes IGN] acquisition de données
[Termes IGN] capteur non-imageur
[Termes IGN] contenu généré par les utilisateurs
[Termes IGN] diffusion de l'information
[Termes IGN] épicentre
[Termes IGN] Etats-Unis
[Termes IGN] production participative
[Termes IGN] séisme
[Termes IGN] surveillance géologique
[Termes IGN] TwitterRésumé : (Auteur) Social media feeds are rapidly emerging as a novel avenue for the contribution and dissemination of information that is often geographic. Their content often includes references to events occurring at, or affecting specific locations. Within this article, we analyze the spatial and temporal characteristics of the twitter feed activity responding to a 5.8 magnitude earthquake which occurred on the East Coast of the United States (US) on August 23, 2011. We argue that these feeds represent a hybrid form of a sensor system that allows for the identification and localization of the impact area of the event. By contrasting this with comparable content collected through the dedicated crowdsourcing ‘Did You Feel It?’ (DYFI) website of the U.S. Geological Survey we assess the potential of the use of harvested social media content for event monitoring. The experiments support the notion that people act as sensors to give us comparable results in a timely manner, and can complement other sources of data to enhance our situational awareness and improve our understanding and response to such events. Numéro de notice : A2013-044 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/SOCIETE NUMERIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01359.x Date de publication en ligne : 09/10/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01359.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32182
in Transactions in GIS > vol 17 n° 1 (February 2013) . - pp 124 - 147[article]A multi-scale approach to mapping canopy height / Gordon M. Green in Photogrammetric Engineering & Remote Sensing, PERS, vol 79 n° 2 (February 2013)
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Titre : A multi-scale approach to mapping canopy height Type de document : Article/Communication Auteurs : Gordon M. Green, Auteur ; C. Ahearn, Auteur ; W. Ni-Meister, Auteur Année de publication : 2013 Article en page(s) : pp 185 - 194 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] analyse multiéchelle
[Termes IGN] base de données d'occupation du sol
[Termes IGN] carte de la végétation
[Termes IGN] données altimétriques
[Termes IGN] données ICEsat
[Termes IGN] données laser
[Termes IGN] Etats-Unis
[Termes IGN] fusion de données
[Termes IGN] hauteur de la végétation
[Termes IGN] occupation du sol
[Termes IGN] service web géographiqueRésumé : (Auteur) Mapping vegetation height over large areas presents a problem of scale: height varies with the individual tree or stand, but the resolution of available datasets is too low to characterize this variability sufficiently for many applications. We address this problem by fusing 1 km resolution canopy height data derived from satellite-based laser altimetry with higher-resolution land-cover data, resulting in 30 m resolution estimates of canopy height. These are downscaled further to 1 m resolution by simulating individual trees. A web service architecture is used, which allows processing to occur on demand without preprocessing large datasets. We compared the resulting canopy volumes to reference airborne lidar data from 262 randomly located 1 km2 areas within nine study sites. Results at 30 m resolution show an RMSE of 33 percent of the mean reference volume and an R2 of 0.77; at 1 m the RMSE is 66 percent and the R2 is 0.38. Numéro de notice : A2013-078 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.79.2.185 En ligne : https://doi.org/10.14358/PERS.79.2.185 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32216
in Photogrammetric Engineering & Remote Sensing, PERS > vol 79 n° 2 (February 2013) . - pp 185 - 194[article]Spatially variable surface elevation changes and estimated melt water contribution of Continental Glacier in the Wind River Range, Wyoming, USA, 1966-2011 / Jeffrey A. Vanlooy in Geocarto international, vol 28 n° 1-2 (February - May 2013)
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Titre : Spatially variable surface elevation changes and estimated melt water contribution of Continental Glacier in the Wind River Range, Wyoming, USA, 1966-2011 Type de document : Article/Communication Auteurs : Jeffrey A. Vanlooy, Auteur ; Richard R. Forster, Auteur ; David Barta, Auteur ; James Turrin, Auteur Année de publication : 2013 Article en page(s) : pp 98 - 113 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] analyse diachronique
[Termes IGN] bassin hydrographique
[Termes IGN] données altimétriques
[Termes IGN] eau de fonte
[Termes IGN] glacier
[Termes IGN] Wyoming (Etats-Unis)Résumé : (Auteur) Seasonal snow melt in the Wind River Range, Wyoming, has been ending earlier over the last several decades leaving the region to rely more on supplemental melt water from mountain glaciers. This leads to the necessity of understanding recent glacial changes. This study uses elevation data from 1966, 2006 and 2011 to calculate surface elevation and volume changes that have occurred on Continental Glacier. Results indicate a mean volume change of -0.034 1 0.02 km3 and surface elevation change of -0.36 1 0.19 m y-1 between 1966 and 2006. Detailed spatial analysis shows that the glacier is divided into two sections which are thinning at different rates (lower section: -0.0610.19 m y-1; upper section: -0.51 1 0.19 m y-1). The upper section has experienced 97% of the thinning (or 742.5 * 103 m3 of melt water equivalent per year) and increased its rate since 2006 by 27.5%. Numéro de notice : A2013-277 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2012.665500 Date de publication en ligne : 05/03/2012 En ligne : https://doi.org/10.1080/10106049.2012.665500 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32415
in Geocarto international > vol 28 n° 1-2 (February - May 2013) . - pp 98 - 113[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 059-2013011 RAB Revue Centre de documentation En réserve L003 Disponible Predicting surface fuel models and fuel metrics using Lidar and CIR imagery in a dense, mountainous forest / Marek Jakubowksi in Photogrammetric Engineering & Remote Sensing, PERS, vol 79 n° 1 (January 2013)
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Titre : Predicting surface fuel models and fuel metrics using Lidar and CIR imagery in a dense, mountainous forest Type de document : Article/Communication Auteurs : Marek Jakubowksi, Auteur ; Quinhua Guo, Auteur ; Brandon Collins, Auteur ; Scott Stephens, Auteur ; Maggi Kelly, Auteur Année de publication : 2013 Article en page(s) : pp 37 - 49 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] biomasse (combustible)
[Termes IGN] Californie (Etats-Unis)
[Termes IGN] classification par séparateurs à vaste marge
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] forêt
[Termes IGN] image multibande
[Termes IGN] image optique
[Termes IGN] interpolation inversement proportionnelle à la distance
[Termes IGN] lutte contre l'incendie
[Termes IGN] montagne
[Termes IGN] PinophytaRésumé : (Auteur) We compared the ability of several classification and regression algorithms to predict forest stand structure metrics and standard surface fuel models. Our study area spans a dense, topographically complex Sierra Nevada mixed-conifer forest. We used clustering, regression trees, and support vector machine algorithms to analyze high density (average 9 pulses/m2), discrete return, small-footprint lidar data, along with multispectral imagery. Stand structure metric predictions generally decreased with increased canopy penetration. For example, from the top of canopy, we predicted canopy height (r2 ! 0.87), canopy cover (r2 ! 0.83), basal area (r2 ! 0.82), shrub cover (r2 ! 0.62), shrub height (r2 ! 0.59), combined fuel loads (r2 ! 0.48), and fuel bed depth (r2 ! 0.35). While the general fuel types were predicted accurately, specific surface fuel model predictions were poor (76 percent and "50 percent correct classification, respectively) using all algorithms. These fuel components are critical inputs for wildfire behavior modeling, which ultimately support forest management decisions. This comprehensive examination of the relative utility of lidar and optical imagery will be useful for forest science and management. Numéro de notice : A2013-004 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.79.1.37 En ligne : http://kellylab.berkeley.edu/storage/papers/2013-Jakubowski-etal-PERS.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32142
in Photogrammetric Engineering & Remote Sensing, PERS > vol 79 n° 1 (January 2013) . - pp 37 - 49[article]Tree species discrimination in tropical forests using airborne imaging spectroscopy / Jean-Baptiste Féret in IEEE Transactions on geoscience and remote sensing, vol 51 n° 1 Tome 1 (January 2013)
[article]
Titre : Tree species discrimination in tropical forests using airborne imaging spectroscopy Type de document : Article/Communication Auteurs : Jean-Baptiste Féret, Auteur ; Gregory P. Asner, Auteur Année de publication : 2013 Article en page(s) : pp 73 - 84 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse discriminante
[Termes IGN] arbre (flore)
[Termes IGN] classification dirigée
[Termes IGN] classification par séparateurs à vaste marge
[Termes IGN] distance de Bhattacharyya
[Termes IGN] espèce végétale
[Termes IGN] forêt tropicale
[Termes IGN] Hawaii (Etats-Unis)
[Termes IGN] image aérienne
[Termes IGN] image hyperspectrale
[Termes IGN] segmentation
[Termes IGN] spectroscopieRésumé : (Auteur) We identify canopy species in a Hawaiian tropical forest using supervised classification applied to airborne hyperspectral imagery acquired with the Carnegie Airborne Observatory-Alpha system. Nonparametric methods (linear and radial basis function support vector machine, artificial neural network, and k-nearest neighbor) and parametric methods (linear, quadratic, and regularized discriminant analysis) are compared for a range of species richness values and training sample sizes. We find a clear advantage in using regularized discriminant analysis, linear discriminant analysis, and support vector machines. No unique optimal classifier was found for all conditions tested, but we highlight the possibility of improving support vector machine classification with a better optimization of its free parameters. We also confirm that a combination of spectral and spatial information increases accuracy of species classification: we combine segmentation and species classification from regularized discriminant analysis to produce a map of the 17 discriminated species. Finally, we compare different methods to assess spectral separability and find a better ability of Bhattacharyya distance to assess separability within and among species. The results indicate that species mapping is tractable in tropical forests when using high-fidelity imaging spectroscopy. Numéro de notice : A2013-010 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2012.2199323 Date de publication en ligne : 16/07/2012 En ligne : https://doi.org/10.1109/TGRS.2012.2199323 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32148
in IEEE Transactions on geoscience and remote sensing > vol 51 n° 1 Tome 1 (January 2013) . - pp 73 - 84[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-2013011A RAB Revue Centre de documentation En réserve L003 Disponible New constraints on the origin of the Hawaiian swell from wavelet analysis of the geoid-to-topography ratio / Cécilia Cadio in Earth and planetary science letters, vol 359–360 (15 December 2012)PermalinkEvaluation of satellite-derived agro-climate variables in the Northern Great Plains of the United States / R. Lemons in Geocarto international, vol 27 n° 8 (December 2012)PermalinkLiDAR-Landsat data fusion for large-area assessment of urban land cover: Balancing spatial resolution, data volume and mapping accuracy / K. Singh in ISPRS Journal of photogrammetry and remote sensing, vol 74 (Novembrer 2012)PermalinkA symmetry detector for map generalization and urban-space analysis / Jan‐Henrik Haunert in ISPRS Journal of photogrammetry and remote sensing, vol 74 (Novembrer 2012)PermalinkThe electronically steerable flash Lidar : A full waveform scanning system for topographic and ecosystem structure applications / H. Duong in IEEE Transactions on geoscience and remote sensing, vol 50 n° 11 Tome 2 (November 2012)PermalinkAn automated system for image-to-vector georeferencing / Y. Li in Cartography and Geographic Information Science, vol 39 n° 4 (October 2012)PermalinkLandscape controls over major nutrients and primary productivity of Arctic lakes / P. Pathak in Cartography and Geographic Information Science, vol 39 n° 4 (October 2012)PermalinkMulti-model validation of currents in the Chesapeake Bay region in June 2010 / P. Chu in Marine geodesy, vol 35 n° 4 (October - December 2012)PermalinkQuantifying urban land cover change between 2001 and 2006 in the Gulf of Mexico region / George Xian in Geocarto international, vol 27 n° 6 (October 2012)PermalinkDecline of forest interior conditions in the conterminous United States / Kurt H. Riitters in Scientific reports, vol 2 (2012)Permalink